Speed table: generic zone-based speed management

- SpeedTable: maps disc positions to optimal speeds
- Default: max speed everywhere (drive manages itself)
- After read_speed_table(): calibrated per-zone speeds
- One u32 comparison per read on hot path
- Error recovery: reduce() / resume() override table temporarily
- Replaces old tier-based speed management in ContentReader
- MT1959 split into mod.rs + variant_a.rs + variant_b.rs
- PlatformDriver: init() + read_speed_table() + is_ready()

src/disc.rs

@@ -774,9 +774,7 @@ pub struct ContentReader<'a> {
     /// Consecutive errors at current position
     error_streak: u32,
     /// Current speed tier index (0 = max, higher = slower)
-    speed_tier: usize,
     /// Last time maintain_speed was called
-    last_speed_maintain: std::time::Instant,
     /// Total read errors encountered
     pub errors: u32,
 }
@@ -823,8 +821,6 @@ impl Disc {
             max_batch_sectors: max_batch,
             ok_streak: 0,
             error_streak: 0,
-            speed_tier: 0,
-            last_speed_maintain: std::time::Instant::now(),
             errors: 0,
         })
     }
@@ -879,15 +875,6 @@ const RAMP_BATCH_AFTER: u32 = 5;     // successes before doubling batch size
 const RAMP_SPEED_AFTER: u32 = 50;    // successes at max batch before restoring speed
 const SLOW_SPEED_AFTER: u32 = 3;     // consecutive errors before reducing disc speed
 
-/// Disc speed tiers (KB/s for SET CD SPEED).
-/// Blu-ray: 1x=4500, 2x=9000, 4x=18000, 8x=36000, 12x=54000
-const SPEED_TIERS: &[u16] = &[
-    0xFFFF, // tier 0: max (drive decides, typically 8-12x)
-    36000,  // tier 1: 8x BD (~36 MB/s)
-    18000,  // tier 2: 4x BD (~18 MB/s)
-    9000,   // tier 3: 2x BD (~9 MB/s)
-    4500,   // tier 4: 1x BD (~4.5 MB/s) — last resort
-];
 
 impl<'a> ContentReader<'a> {
     /// Total bytes across all extents (for progress display).
@@ -973,29 +960,10 @@ impl<'a> ContentReader<'a> {
         Ok(())
     }
 
-    /// Set disc spin speed via SCSI SET CD SPEED.
-    fn set_speed(&mut self, tier: usize) {
-        let tier = tier.min(SPEED_TIERS.len() - 1);
-        if tier != self.speed_tier {
-            self.speed_tier = tier;
-            let speed_kbs = SPEED_TIERS[tier];
-            let cdb = crate::scsi::build_set_cd_speed(speed_kbs);
-            let mut dummy = [0u8; 0];
-            let _ = self.session.scsi_execute(
-                &cdb, crate::scsi::DataDirection::None, &mut dummy, 5_000,
-            );
-        }
-    }
-
     /// Read a batch of sectors into the internal buffer.
     ///
-    /// Adaptive strategy:
-    ///   1. Read at current batch size
-    ///   2. On success: ramp batch up (double after 5 successes),
-    ///      then restore disc speed (after 50 at max batch)
-    ///   3. On error: halve batch, pause. After 3 consecutive errors,
-    ///      also reduce disc spin speed (scratched/damaged region).
-    ///   4. At min batch + still failing: retry once, then skip + zero-fill.
+    /// Speed management: speed table checked before each read.
+    /// On error: reduce speed, halve batch. On recovery: resume from table.
     fn fill_buffer(&mut self) -> Result<bool> {
         loop {
             if self.current_extent >= self.extents.len() {
@@ -1019,6 +987,15 @@ impl<'a> ContentReader<'a> {
             let byte_count = sectors_to_read as usize * 2048;
             self.read_buf.resize(byte_count, 0);
 
+            // Check speed table — send SET_CD_SPEED if zone changed
+            if let Some(speed_kbs) = self.session.speed_table.speed_for(lba) {
+                let cdb = crate::scsi::build_set_cd_speed(speed_kbs);
+                let mut dummy = [0u8; 0];
+                let _ = self.session.scsi_execute(
+                    &cdb, crate::scsi::DataDirection::None, &mut dummy, 5_000,
+                );
+            }
+
             match self.read_sectors(lba, sectors_to_read) {
                 Ok(_) => {
                     self.buf_len = sectors_to_read as usize / 3;
@@ -1031,19 +1008,18 @@ impl<'a> ContentReader<'a> {
                         self.current_offset = 0;
                     }
 
-                    // Ramp up: batch size first, then disc speed
+                    // Ramp up batch size after consecutive successes
                     self.ok_streak += 1;
-                    if self.batch_sectors < self.max_batch_sectors {
-                        if self.ok_streak >= RAMP_BATCH_AFTER {
-                            self.batch_sectors = (self.batch_sectors * 2).min(self.max_batch_sectors);
-                            self.ok_streak = 0;
-                        }
-                    } else if self.speed_tier > 0 && self.ok_streak >= RAMP_SPEED_AFTER {
-                        // At max batch for a while — try faster disc speed
-                        self.set_speed(self.speed_tier - 1);
+                    if self.batch_sectors < self.max_batch_sectors && self.ok_streak >= RAMP_BATCH_AFTER {
+                        self.batch_sectors = (self.batch_sectors * 2).min(self.max_batch_sectors);
                         self.ok_streak = 0;
                     }
 
+                    // Resume table-driven speed after sustained success
+                    if self.error_streak == 0 && self.ok_streak >= RAMP_SPEED_AFTER {
+                        self.session.speed_table.resume(lba);
+                    }
+
                     return Ok(true);
                 }
                 Err(_) => {
@@ -1051,11 +1027,14 @@ impl<'a> ContentReader<'a> {
                     self.error_streak += 1;
                     self.ok_streak = 0;
 
-                    // Reduce disc speed after repeated errors (physical problem)
-                    if self.error_streak >= SLOW_SPEED_AFTER
-                        && self.speed_tier < SPEED_TIERS.len() - 1
-                    {
-                        self.set_speed(self.speed_tier + 1);
+                    // Reduce speed after repeated errors
+                    if self.error_streak >= SLOW_SPEED_AFTER {
+                        let speed = self.session.speed_table.reduce();
+                        let cdb = crate::scsi::build_set_cd_speed(speed);
+                        let mut dummy = [0u8; 0];
+                        let _ = self.session.scsi_execute(
+                            &cdb, crate::scsi::DataDirection::None, &mut dummy, 5_000,
+                        );
                         self.error_streak = 0; // reset — give new speed a chance
                     }
 

src/drive.rs

@@ -12,10 +12,12 @@ use crate::identity::DriveId;
 use crate::profile::{self, DriveProfile, ProfileMatch};
 use crate::platform::PlatformDriver;
 use crate::platform::mt1959::Mt1959;
+use crate::speed::SpeedTable;
 
 pub struct DriveSession {
     scsi: Box<dyn ScsiTransport>,
     driver: Box<dyn PlatformDriver>,
+    pub speed_table: SpeedTable,
     pub profile: DriveProfile,
     pub platform: profile::Platform,
     pub drive_id: DriveId,
@@ -40,6 +42,7 @@ impl DriveSession {
         Ok(DriveSession {
             scsi: transport,
             driver,
+            speed_table: SpeedTable::new(),
             platform: m.platform,
             profile: m.profile,
             drive_id,
@@ -71,16 +74,19 @@ impl DriveSession {
         &self.device_path
     }
 
+    /// Initialize drive — unlock + firmware upload.
     pub fn init(&mut self) -> Result<()> {
         self.driver.init(self.scsi.as_mut())
     }
 
-    pub fn is_ready(&self) -> bool {
-        self.driver.is_ready()
+    /// Read speed zones from disc into speed table.
+    /// Requires init() first. Optional — without this, drive manages speed itself.
+    pub fn read_speed_table(&mut self) -> Result<()> {
+        self.driver.read_speed_table(self.scsi.as_mut(), &mut self.speed_table)
     }
 
-    pub fn set_read_speed(&mut self, lba: u32) -> Result<()> {
-        self.driver.set_read_speed(self.scsi.as_mut(), lba)
+    pub fn is_ready(&self) -> bool {
+        self.driver.is_ready()
     }
 
     pub fn read_disc(&mut self, lba: u32, count: u16, buf: &mut [u8]) -> Result<usize> {

src/platform/mod.rs

@@ -1,22 +1,18 @@
-//! Platform-specific drive initialization and speed management.
-//!
-//! The Platform trait is minimal by design. Callers use init() once,
-//! then set_read_speed() during reads. Internal operations cannot be
-//! called directly — this prevents out-of-sequence operations.
+//! Platform-specific drive initialization and calibration.
 
 pub mod mt1959;
 
 use crate::error::Result;
 use crate::scsi::ScsiTransport;
+use crate::speed::SpeedTable;
 
-/// Platform trait — locked-down interface.
-///
-/// Only three operations exposed:
-///   init()           — one-time initialization
-///   set_read_speed() — per-zone speed during reads
-///   is_ready()       — state check
 pub(crate) trait PlatformDriver {
+    /// Unlock drive + upload firmware if needed.
     fn init(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()>;
-    fn set_read_speed(&mut self, scsi: &mut dyn ScsiTransport, lba: u32) -> Result<()>;
+
+    /// Read speed zones from disc surface, fill speed table.
+    fn read_speed_table(&mut self, scsi: &mut dyn ScsiTransport, speed_table: &mut SpeedTable) -> Result<()>;
+
+    /// True after successful init().
     fn is_ready(&self) -> bool;
 }

src/platform/mt1959/mod.rs

@@ -1,27 +1,27 @@
-//! MT1959 platform — unlock, firmware upload, calibration, speed management.
+//! MT1959 platform — shared logic for both variants.
+
+mod variant_a;
+mod variant_b;
 
 use crate::error::{Error, Result};
 use crate::profile::DriveProfile;
 use crate::scsi::{self, DataDirection, ScsiTransport};
+use crate::speed::SpeedTable;
 use super::PlatformDriver;
 
 const UNLOCK_RESPONSE_SIZE: u8 = 64;
-
-// Variant constants
 const MODE_A: u8 = 0x01;
 const MODE_B: u8 = 0x02;
 const BUFFER_ID_A: u8 = 0x44;
 const BUFFER_ID_B: u8 = 0x77;
 const NOMINAL_SPEED_A: [u8; 12] = [0xBB, 0x00, 0x23, 0x28, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00];
 const NOMINAL_SPEED_B: [u8; 12] = [0x00, 0x00, 0xBB, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00];
-const FIRMWARE_EXTRA_B: [u8; 16] = [0; 16];
-const VERIFY_COMMAND_B: [u8; 10] = [0xF1, 0x01, 0x02, 0x00, 0x0D, 0x30, 0x01, 0xF3, 0xAD, 0x23];
 
 pub struct Mt1959 {
-    profile: DriveProfile,
-    mode: u8,
-    buffer_id: u8,
-    unlocked: bool,
+    pub(crate) profile: DriveProfile,
+    pub(crate) mode: u8,
+    pub(crate) buffer_id: u8,
+    pub(crate) unlocked: bool,
     speed_table: [u16; 64],
     disc_sectors: u32,
     calibrated: bool,
@@ -36,9 +36,7 @@ impl Mt1959 {
             (MODE_A, BUFFER_ID_A)
         };
         Mt1959 {
-            profile,
-            mode,
-            buffer_id,
+            profile, mode, buffer_id,
             unlocked: false,
             speed_table: [0u16; 64],
             disc_sectors: 0,
@@ -47,7 +45,9 @@ impl Mt1959 {
         }
     }
 
-    fn read_buffer_sub(&self, sub_cmd: u8, address: u16, length: u8) -> [u8; 10] {
+    // ── SCSI helpers (shared by both variants) ─────────────────────────
+
+    pub(crate) fn read_buffer_sub(&self, sub_cmd: u8, address: u16, length: u8) -> [u8; 10] {
         [
             0x3C, self.mode, self.buffer_id, sub_cmd,
             (address >> 8) as u8, address as u8,
@@ -55,7 +55,7 @@ impl Mt1959 {
         ]
     }
 
-    fn read_buffer_probe(
+    pub(crate) fn read_buffer_probe(
         &self, scsi: &mut dyn ScsiTransport,
         sub_cmd: u8, address: u16, buf: &mut [u8], expected: usize,
     ) -> Result<usize> {
@@ -67,21 +67,16 @@ impl Mt1959 {
         Ok(result.bytes_transferred)
     }
 
-    fn set_cd_speed_max(&self, scsi: &mut dyn ScsiTransport) -> Result<()> {
+    pub(crate) fn set_cd_speed_max(&self, scsi: &mut dyn ScsiTransport) -> Result<()> {
         let cdb = scsi::build_set_cd_speed(0xFFFF);
         let mut dummy = [0u8; 0];
         scsi.execute(&cdb, DataDirection::None, &mut dummy, 5_000)?;
         Ok(())
     }
 
-    fn set_cd_speed(&self, scsi: &mut dyn ScsiTransport, speed: u16) -> Result<()> {
-        let cdb = scsi::build_set_cd_speed(speed);
-        let mut dummy = [0u8; 0];
-        scsi.execute(&cdb, DataDirection::None, &mut dummy, 5_000)?;
-        Ok(())
-    }
+    // ── Unlock (shared) ────────────────────────────────────────────────
 
-    fn do_unlock(&mut self, scsi: &mut dyn ScsiTransport) -> Result<Vec<u8>> {
+    pub(crate) fn do_unlock(&mut self, scsi: &mut dyn ScsiTransport) -> Result<Vec<u8>> {
         let cdb = [
             0x3C, self.mode, self.buffer_id,
             0x00, 0x00, 0x00,
@@ -124,49 +119,38 @@ impl Mt1959 {
         }
         Err(Error::ScsiError { opcode: 0x3C, status: 0xFF, sense_key: 0 })
     }
-}
 
-impl PlatformDriver for Mt1959 {
-    fn init(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
-        if self.unlocked && self.calibrated {
-            return Ok(());
+    // ── Init (unlock + firmware) ───────────────────────────────────────
+
+    fn run_init(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
+        let mut unlocked = false;
+        for _attempt in 0..6 {
+            match self.do_unlock(scsi) {
+                Ok(_) => { unlocked = true; break; }
+                Err(Error::SignatureMismatch { .. }) => {
+                    return Err(Error::UnlockFailed {
+                        detail: "signature mismatch — wrong profile for this drive".into(),
+                    });
+                }
+                Err(_) => {
+                    let ok = if self.mode == MODE_A {
+                        variant_a::load_firmware(self, scsi).is_ok()
+                    } else {
+                        variant_b::load_firmware(self, scsi).is_ok()
+                    };
+                    if ok { unlocked = true; break; }
+                }
+            }
         }
-        self.run_init(scsi)
-    }
-
-    fn set_read_speed(&mut self, scsi: &mut dyn ScsiTransport, lba: u32) -> Result<()> {
-        if !self.calibrated {
-            return Ok(());
+        if !unlocked {
+            return Err(Error::UnlockFailed { detail: "failed after 6 attempts".into() });
         }
-        self.run_set_read_speed(scsi, lba)
-    }
-
-    fn is_ready(&self) -> bool {
-        self.unlocked && self.calibrated
-    }
-}
-
-impl Mt1959 {
-    fn unlock(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
-        self.do_unlock(scsi)?;
         Ok(())
     }
 
-    fn load_firmware(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
-        if self.profile.firmware.is_empty() {
-            return Err(Error::UnlockFailed {
-                detail: "no firmware in profile".into(),
-            });
-        }
+    // ── Calibrate (disc surface probes) ────────────────────────────────
 
-        if self.mode == MODE_A {
-            self.load_firmware_a(scsi)
-        } else {
-            self.load_firmware_b(scsi)
-        }
-    }
-
-    fn calibrate(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
+    fn run_calibrate(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
         if !self.unlocked { self.do_unlock(scsi)?; }
 
         let cap_cdb = [0x25u8, 0, 0, 0, 0, 0, 0, 0, 0, 0];
@@ -175,7 +159,7 @@ impl Mt1959 {
             self.disc_sectors = u32::from_be_bytes([cap_buf[0], cap_buf[1], cap_buf[2], cap_buf[3]]) + 1;
         }
 
-        let init_addr: u16 = 0x0100; // TODO: detect disc type (0x0200 for UHD)
+        let init_addr: u16 = 0x0100;
         let mut init_resp = [0u8; 4];
         let _ = self.read_buffer_probe(scsi, 0x12, init_addr, &mut init_resp, 4);
 
@@ -198,9 +182,7 @@ impl Mt1959 {
                 self.calibration_config = [0u8; 4];
                 return Err(Error::ScsiError { opcode: 0x3C, status: 0xFF, sense_key: 0 });
             }
-            if resp[0] != prev_speed {
-                prev_speed = resp[0];
-            }
+            if resp[0] != prev_speed { prev_speed = resp[0]; }
             addr = addr.wrapping_add(0x100);
         }
 
@@ -232,135 +214,36 @@ impl Mt1959 {
         self.calibrated = true;
         Ok(())
     }
+}
 
-    fn run_set_read_speed(&mut self, scsi: &mut dyn ScsiTransport, lba: u32) -> Result<()> {
-        if !self.calibrated {
-            return Ok(());
-        }
+// ── PlatformDriver trait ───────────────────────────────────────────────
 
-        let mut best_idx: usize = 0;
-        let mut best_diff: u32 = 0x10000000;
-        let mut found = false;
+impl PlatformDriver for Mt1959 {
+    fn init(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
+        if self.unlocked { return Ok(()); }
+        self.run_init(scsi)
+    }
 
+    fn read_speed_table(&mut self, scsi: &mut dyn ScsiTransport, speed_table: &mut SpeedTable) -> Result<()> {
+        if !self.unlocked { self.run_init(scsi)?; }
+        if self.calibrated { return Ok(()); }
+        self.run_calibrate(scsi)?;
+
+        let mut probes: Vec<(u16, u8)> = Vec::new();
         for i in 0..64 {
-            let entry = self.speed_table[i] as u32;
-            if entry == 0 { continue; }
-            let diff = if lba > entry { lba - entry } else { entry - lba };
-            if diff < best_diff {
-                best_diff = diff;
-                best_idx = i;
-                found = true;
-            }
+            let addr = self.speed_table[i];
+            if addr == 0 { continue; }
+            let speed_idx = ((i + 1) << 1) as u8;
+            probes.push((addr, speed_idx));
         }
-
-        if !found {
-            return Ok(());
-        }
-
-        let speed_val = self.speed_table[best_idx];
-        let probe_addr = 0x0100 | (speed_val.swap_bytes() as u16);
-        let mut probe_resp = [0u8; 4];
-        let _ = self.read_buffer_probe(scsi, 0x14, probe_addr, &mut probe_resp, 4);
-
-        let _ = self.set_cd_speed_max(scsi);
-        let _ = self.set_cd_speed(scsi, speed_val);
+        const PROBE_RANGE: u32 = 0x10000;
+        const BD_1X_KBS: u16 = 4500;
+        speed_table.load_calibration(self.disc_sectors, &probes, PROBE_RANGE, BD_1X_KBS);
 
         Ok(())
     }
 
-    fn run_init(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
-        let mut unlocked = false;
-        for _attempt in 0..6 {
-            match self.unlock(scsi) {
-                Ok(_) => { unlocked = true; break; }
-                Err(Error::SignatureMismatch { .. }) => {
-                    return Err(Error::UnlockFailed {
-                        detail: "signature mismatch — wrong profile for this drive".into(),
-                    });
-                }
-                Err(_) => {
-                    if self.load_firmware(scsi).is_ok() {
-                        unlocked = true;
-                        break;
-                    }
-                }
-            }
-        }
-        if !unlocked {
-            return Err(Error::UnlockFailed {
-                detail: "failed after 6 attempts".into(),
-            });
-        }
-
-        let mut calibrated = false;
-        for _attempt in 0..6 {
-            if self.calibrate(scsi).is_ok() {
-                calibrated = true;
-                break;
-            }
-        }
-        if !calibrated {
-            return Err(Error::ScsiError { opcode: 0x3C, status: 0xFF, sense_key: 0 });
-        }
-
-        Ok(())
-    }
-}
-
-impl Mt1959 {
-    fn load_firmware_a(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
-        let firmware = &self.profile.firmware;
-        let len = firmware.len();
-
-        let cdb = [
-            0x3B, 0x06, 0x00,
-            0x00, 0x00, 0x00,
-            (len >> 16) as u8, (len >> 8) as u8, len as u8,
-            0x00,
-        ];
-        let mut data = firmware.clone();
-        scsi.execute(&cdb, DataDirection::ToDevice, &mut data, 30_000)?;
-
-        let verify_cdb = [0x3C, 0x01, 0x45, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00];
-        let mut verify_resp = [0u8; 4];
-        let _ = scsi.execute(&verify_cdb, DataDirection::FromDevice, &mut verify_resp, 5_000);
-
-        self.do_unlock(scsi)?;
-        self.do_unlock(scsi)?;
-        Ok(())
-    }
-
-    fn load_firmware_b(&mut self, scsi: &mut dyn ScsiTransport) -> Result<()> {
-        let firmware = &self.profile.firmware;
-
-        let write_len = 0x9C0usize.min(firmware.len());
-        let mode_select_cdb = [
-            0x55, 0x10, 0x00,
-            0x00, 0x00, 0x00,
-            (write_len >> 16) as u8, (write_len >> 8) as u8, write_len as u8,
-            0x00,
-        ];
-        let mut data = firmware[..write_len].to_vec();
-        scsi.execute(&mode_select_cdb, DataDirection::ToDevice, &mut data, 30_000)?;
-
-        let read_meta_cdb = [0x3C, 0x06, 0x00, 0x00, 0x30, 0x00, 0x00, 0x00, 0x10, 0x00];
-        let mut meta_resp = [0u8; 16];
-        let _ = scsi.execute(&read_meta_cdb, DataDirection::FromDevice, &mut meta_resp, 5_000);
-
-        let write2_cdb = [0x3B, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00];
-        let mut data2 = FIRMWARE_EXTRA_B.to_vec();
-        let _ = scsi.execute(&write2_cdb, DataDirection::ToDevice, &mut data2, 5_000);
-
-        let mut dummy = [0u8; 0];
-        let _ = scsi.execute(&VERIFY_COMMAND_B, DataDirection::None, &mut dummy, 5_000);
-
-        for _attempt in 0..5 {
-            if self.do_unlock(scsi).is_ok() {
-                let _ = self.do_unlock(scsi);
-                return Ok(());
-            }
-        }
-        self.do_unlock(scsi)?;
-        Ok(())
+    fn is_ready(&self) -> bool {
+        self.unlocked
     }
 }

src/platform/mt1959/variant_a.rs

@@ -0,0 +1,33 @@
+//! MT1959 variant A firmware upload.
+
+use crate::error::Result;
+use crate::scsi::{DataDirection, ScsiTransport};
+use super::Mt1959;
+
+pub(super) fn load_firmware(mt: &mut Mt1959, scsi: &mut dyn ScsiTransport) -> Result<()> {
+    let firmware = &mt.profile.firmware;
+    if firmware.is_empty() {
+        return Err(crate::error::Error::UnlockFailed {
+            detail: "no firmware in profile".into(),
+        });
+    }
+
+    let len = firmware.len();
+    let cdb = [
+        0x3B, 0x06, 0x00,
+        0x00, 0x00, 0x00,
+        (len >> 16) as u8, (len >> 8) as u8, len as u8,
+        0x00,
+    ];
+    let mut data = firmware.clone();
+    scsi.execute(&cdb, DataDirection::ToDevice, &mut data, 30_000)?;
+
+    // Verify (may fail, non-fatal)
+    let verify_cdb = [0x3C, 0x01, 0x45, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00];
+    let mut verify_resp = [0u8; 4];
+    let _ = scsi.execute(&verify_cdb, DataDirection::FromDevice, &mut verify_resp, 5_000);
+
+    mt.do_unlock(scsi)?;
+    mt.do_unlock(scsi)?;
+    Ok(())
+}

src/platform/mt1959/variant_b.rs

@@ -0,0 +1,52 @@
+//! MT1959 variant B firmware upload.
+
+use crate::error::Result;
+use crate::scsi::{DataDirection, ScsiTransport};
+use super::Mt1959;
+
+const FIRMWARE_EXTRA: [u8; 16] = [0; 16];
+const VERIFY_COMMAND: [u8; 10] = [0xF1, 0x01, 0x02, 0x00, 0x0D, 0x30, 0x01, 0xF3, 0xAD, 0x23];
+
+pub(super) fn load_firmware(mt: &mut Mt1959, scsi: &mut dyn ScsiTransport) -> Result<()> {
+    let firmware = &mt.profile.firmware;
+    if firmware.is_empty() {
+        return Err(crate::error::Error::UnlockFailed {
+            detail: "no firmware in profile".into(),
+        });
+    }
+
+    // Step 1: MODE SELECT with firmware payload
+    let write_len = 0x9C0usize.min(firmware.len());
+    let mode_select_cdb = [
+        0x55, 0x10, 0x00,
+        0x00, 0x00, 0x00,
+        (write_len >> 16) as u8, (write_len >> 8) as u8, write_len as u8,
+        0x00,
+    ];
+    let mut data = firmware[..write_len].to_vec();
+    scsi.execute(&mode_select_cdb, DataDirection::ToDevice, &mut data, 30_000)?;
+
+    // Step 2: Read firmware metadata
+    let read_meta_cdb = [0x3C, 0x06, 0x00, 0x00, 0x30, 0x00, 0x00, 0x00, 0x10, 0x00];
+    let mut meta_resp = [0u8; 16];
+    let _ = scsi.execute(&read_meta_cdb, DataDirection::FromDevice, &mut meta_resp, 5_000);
+
+    // Step 3: Write extra firmware data
+    let write2_cdb = [0x3B, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00];
+    let mut data2 = FIRMWARE_EXTRA.to_vec();
+    let _ = scsi.execute(&write2_cdb, DataDirection::ToDevice, &mut data2, 5_000);
+
+    // Step 4: Vendor verify
+    let mut dummy = [0u8; 0];
+    let _ = scsi.execute(&VERIFY_COMMAND, DataDirection::None, &mut dummy, 5_000);
+
+    // Step 5: Unlock retries
+    for _attempt in 0..5 {
+        if mt.do_unlock(scsi).is_ok() {
+            let _ = mt.do_unlock(scsi);
+            return Ok(());
+        }
+    }
+    mt.do_unlock(scsi)?;
+    Ok(())
+}

src/speed.rs

@@ -1,41 +1,141 @@
-//! Drive speed control — query and set read speeds.
+//! Drive speed management — zone-based speed table.
 //!
-//! Uses MMC-6 SET CD SPEED (0xBB) command.
-//! Reference: MMC-6 §6.30
+//! Every DriveSession has a SpeedTable. Default: max speed everywhere.
+//! After init(): calibrated per-zone speeds from disc surface probes.
+//! One u32 comparison per read on the hot path.
 
-/// Disc read speed.
+/// Speed table — maps disc positions to optimal read speeds.
+#[derive(Debug, Clone)]
+pub struct SpeedTable {
+    zones: Vec<(u32, u16)>,  // (start_lba, speed_kbs), sorted by lba
+    current_speed: u16,
+    next_boundary: u32,
+}
+
+impl SpeedTable {
+    /// Default: max speed, whole disc. Drive manages itself.
+    pub fn new() -> Self {
+        SpeedTable {
+            zones: vec![(0, 0xFFFF)],
+            current_speed: 0,       // force first SET_CD_SPEED
+            next_boundary: 0,       // force first lookup
+        }
+    }
+
+    /// Hot path: has the speed zone changed for this LBA?
+    /// Returns Some(speed_kbs) only when a SET_CD_SPEED is needed.
+    #[inline]
+    pub fn speed_for(&mut self, lba: u32) -> Option<u16> {
+        if lba < self.next_boundary {
+            return None;
+        }
+        self.transition(lba)
+    }
+
+    /// Zone transition — lookup + precompute next boundary.
+    fn transition(&mut self, lba: u32) -> Option<u16> {
+        let mut zone_idx = 0;
+        for (i, &(start, _)) in self.zones.iter().enumerate() {
+            if start <= lba {
+                zone_idx = i;
+            } else {
+                break;
+            }
+        }
+
+        let speed = self.zones[zone_idx].1;
+
+        self.next_boundary = if zone_idx + 1 < self.zones.len() {
+            self.zones[zone_idx + 1].0
+        } else {
+            u32::MAX
+        };
+
+        if speed == self.current_speed {
+            return None;
+        }
+
+        self.current_speed = speed;
+        Some(speed)
+    }
+
+    /// Load calibrated zones. Converts from platform probe data to generic (lba, kbs).
+    /// `disc_sectors`: total disc capacity from READ CAPACITY.
+    /// `probes`: (probe_address, speed_index) pairs from calibration scan.
+    /// `probe_range`: max probe address space (0x10000 for MT1959).
+    /// `speed_multiplier`: KB/s per speed unit (4500 for BD 1x).
+    pub fn load_calibration(
+        &mut self,
+        disc_sectors: u32,
+        probes: &[(u16, u8)],
+        probe_range: u32,
+        speed_multiplier: u16,
+    ) {
+        if probes.is_empty() || disc_sectors == 0 {
+            return;
+        }
+
+        let mut zones: Vec<(u32, u16)> = Vec::new();
+
+        for &(probe_addr, speed_idx) in probes {
+            let lba = (probe_addr as u64 * disc_sectors as u64 / probe_range as u64) as u32;
+            let kbs = speed_idx as u16 * speed_multiplier;
+            zones.push((lba, kbs));
+        }
+
+        zones.sort_by_key(|&(lba, _)| lba);
+
+        // Deduplicate: keep only zone boundaries where speed changes
+        let mut deduped: Vec<(u32, u16)> = Vec::new();
+        for &(lba, kbs) in &zones {
+            if deduped.last().map_or(true, |&(_, prev_kbs)| prev_kbs != kbs) {
+                deduped.push((lba, kbs));
+            }
+        }
+
+        if deduped.is_empty() {
+            return;
+        }
+
+        self.zones = deduped;
+        self.current_speed = 0;
+        self.next_boundary = 0;
+    }
+
+    /// Temporarily reduce speed for error recovery.
+    pub fn reduce(&mut self) -> u16 {
+        let speed = (self.current_speed / 2).max(4500);
+        self.current_speed = speed;
+        speed
+    }
+
+    /// Resume table-driven speed at this LBA.
+    pub fn resume(&mut self, lba: u32) {
+        self.current_speed = 0;
+        self.next_boundary = 0;
+        self.transition(lba);
+    }
+
+    /// Current speed in KB/s.
+    pub fn current(&self) -> u16 {
+        self.current_speed
+    }
+
+    /// Number of zones.
+    pub fn zone_count(&self) -> usize {
+        self.zones.len()
+    }
+}
+
+// Keep DriveSpeed enum for CLI display
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub enum DriveSpeed {
-    /// Blu-ray 1x = 4,500 KB/s
-    BD1x,
-    /// Blu-ray 2x = 9,000 KB/s
-    BD2x,
-    /// Blu-ray 4x = 18,000 KB/s
-    BD4x,
-    /// Blu-ray 6x = 27,000 KB/s
-    BD6x,
-    /// Blu-ray 8x = 36,000 KB/s
-    BD8x,
-    /// Blu-ray 10x = 45,000 KB/s
-    BD10x,
-    /// Blu-ray 12x = 54,000 KB/s
-    BD12x,
-    /// DVD 1x = 1,385 KB/s
-    DVD1x,
-    /// DVD 2x = 2,770 KB/s
-    DVD2x,
-    /// DVD 4x = 5,540 KB/s
-    DVD4x,
-    /// DVD 8x = 11,080 KB/s
-    DVD8x,
-    /// DVD 16x = 22,160 KB/s
-    DVD16x,
-    /// Maximum speed — drive decides
+    BD1x, BD2x, BD4x, BD6x, BD8x, BD10x, BD12x,
+    DVD1x, DVD2x, DVD4x, DVD8x, DVD16x,
     Max,
 }
 
 impl DriveSpeed {
-    /// Convert to KB/s for MMC-6 SET CD SPEED command.
     pub fn to_kbps(self) -> u16 {
         match self {
             DriveSpeed::BD1x   => 4_500,
@@ -53,71 +153,10 @@ impl DriveSpeed {
             DriveSpeed::Max    => 0xFFFF,
         }
     }
-
-    /// Create from KB/s value, rounding to nearest standard speed.
-    pub fn from_kbps(kbps: u16) -> Self {
-        match kbps {
-            0..=2_000         => DriveSpeed::DVD1x,
-            2_001..=4_000     => DriveSpeed::DVD2x,
-            4_001..=6_000     => DriveSpeed::BD1x,
-            6_001..=13_000    => DriveSpeed::BD2x,
-            13_001..=22_000   => DriveSpeed::BD4x,
-            22_001..=31_000   => DriveSpeed::BD6x,
-            31_001..=40_000   => DriveSpeed::BD8x,
-            40_001..=49_000   => DriveSpeed::BD10x,
-            49_001..=u16::MAX => DriveSpeed::BD12x,
-        }
-    }
-
-    /// Human-readable label.
-    pub fn label(&self) -> &'static str {
-        match self {
-            DriveSpeed::BD1x   => "BD 1x",
-            DriveSpeed::BD2x   => "BD 2x",
-            DriveSpeed::BD4x   => "BD 4x",
-            DriveSpeed::BD6x   => "BD 6x",
-            DriveSpeed::BD8x   => "BD 8x",
-            DriveSpeed::BD10x  => "BD 10x",
-            DriveSpeed::BD12x  => "BD 12x",
-            DriveSpeed::DVD1x  => "DVD 1x",
-            DriveSpeed::DVD2x  => "DVD 2x",
-            DriveSpeed::DVD4x  => "DVD 4x",
-            DriveSpeed::DVD8x  => "DVD 8x",
-            DriveSpeed::DVD16x => "DVD 16x",
-            DriveSpeed::Max    => "Max",
-        }
-    }
-
-    /// All standard Blu-ray speeds.
-    pub fn all_bd() -> &'static [DriveSpeed] {
-        &[DriveSpeed::BD1x, DriveSpeed::BD2x, DriveSpeed::BD4x,
-          DriveSpeed::BD6x, DriveSpeed::BD8x, DriveSpeed::BD10x, DriveSpeed::BD12x]
-    }
-
-    /// All standard DVD speeds.
-    pub fn all_dvd() -> &'static [DriveSpeed] {
-        &[DriveSpeed::DVD1x, DriveSpeed::DVD2x, DriveSpeed::DVD4x,
-          DriveSpeed::DVD8x, DriveSpeed::DVD16x]
-    }
 }
 
 impl std::fmt::Display for DriveSpeed {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{} ({} KB/s)", self.label(), self.to_kbps())
+        write!(f, "{:?} ({} KB/s)", self, self.to_kbps())
     }
 }
-
-/// Build SET CD SPEED CDB — MMC-6 §6.30
-pub fn set_cd_speed_cdb(read_speed: DriveSpeed) -> [u8; 12] {
-    let kbps = read_speed.to_kbps();
-    [
-        0xBB,                       // SET CD SPEED opcode
-        0x00,                       // reserved
-        (kbps >> 8) as u8,          // read speed MSB
-        kbps as u8,                 // read speed LSB
-        0xFF,                       // write speed MSB (0xFFFF = don't change)
-        0xFF,                       // write speed LSB
-        0x00, 0x00, 0x00, 0x00,    // reserved
-        0x00, 0x00,                 // reserved
-    ]
-}