Index: debug-as3525.c
===================================================================
--- debug-as3525.c	(revision 27164)
+++ debug-as3525.c	(working copy)
@@ -268,6 +268,30 @@
     {
         while(1)
         {
+        int i;
+        extern int sd_cmds_submitted[NUM_VOLUMES];
+        extern int sd_cmds_errors[NUM_VOLUMES];
+        extern int sd_transfers[NUM_VOLUMES];
+        extern int sd_transfer_errors[NUM_VOLUMES];
+        lcd_clear_display();
+        line = 0;
+        lcd_puts(0, line++, "[SD error stats]");
+        for (i=0; i<NUM_VOLUMES; i++) {
+            lcd_putsf(0, line++, "Drive %d errors:", i);
+            lcd_putsf(0, line++, "cmd %d of %d",
+                       sd_cmds_errors[i], sd_cmds_submitted[i]);
+            lcd_putsf(0, line++, "r/w %d of %d",
+                      sd_transfer_errors[i], sd_transfers[i]);
+        }
+        lcd_update();
+        int btn = button_get_w_tmo(HZ/10);
+        if(btn == (DEBUG_CANCEL|BUTTON_REL))
+            goto end;
+        else if(btn == (BUTTON_DOWN|BUTTON_REL))
+            break;
+        }
+        while(1)
+        {
 #ifdef SANSA_C200V2
         lcd_clear_display();
         line = 0;
Index: sd-as3525.c
===================================================================
--- sd-as3525.c	(revision 27165)
+++ sd-as3525.c	(working copy)
@@ -126,6 +126,11 @@
 static struct event_queue sd_queue;
 bool sd_enabled = false;
 
+int sd_cmds_submitted[NUM_VOLUMES];
+int sd_cmds_errors[NUM_VOLUMES];
+int sd_transfers[NUM_VOLUMES];
+int sd_transfer_errors[NUM_VOLUMES];
+
 #if defined(HAVE_MULTIDRIVE)
 static bool hs_card = false;
 #define EXT_SD_BITS (1<<2)
@@ -174,7 +179,7 @@
 {
     static struct timeout sd1_oneshot;
     if (GPIOA_MIS & EXT_SD_BITS)
-        timeout_register(&sd1_oneshot, sd1_oneshot_callback, (3*HZ/10), 0);
+        timeout_register(&sd1_oneshot, sd1_oneshot_callback, (9*HZ/10), 0);
     /* acknowledge interrupt */
     GPIOA_IC = EXT_SD_BITS;
 }
@@ -207,6 +212,8 @@
 {
     int status;
 
+    sd_cmds_submitted[drive]++;
+
     unsigned cmd_retries = 6;
     while(cmd_retries--)
     {
@@ -236,8 +243,10 @@
         {
             response[0] = MCI_RESP0(drive); /* Always prepare short response */
 
-            if(status & MCI_RESPONSE_ERROR) /* timeout or crc failure */
+            if(status & MCI_RESPONSE_ERROR) {/* timeout or crc failure */
+                sd_cmds_errors[drive]++;
                 continue;
+            }
 
             if(status & MCI_CMD_RESP_END)   /* Response passed CRC check */
             {
@@ -257,6 +266,32 @@
     return false;
 }
 
+static void sd_set_widebus_mode(IF_MD2(int drive,) int on) {
+#ifndef HAVE_MULTIDRIVE
+    const int drive = 0;
+#endif
+    long response = 0;
+    int ret;
+    if((ret = sd_wait_for_tran_state(drive)) < 0) {
+        int ret2 = send_cmd(drive, SD_SEND_STATUS, card_info[drive].rca,
+                            MCI_RESP, &response);
+        panicf("sd_set_widebus(%d): tran: %d %d %lx %lx", on, ret, ret2, response, MCI_STATUS(drive));
+    }
+    /* CMD55 */              /*  Response is requested due to timing issue  */
+    if(!send_cmd(drive, SD_APP_CMD, card_info[drive].rca, MCI_RESP, &response))
+        panicf("sd_set_widebus(%d): app_cmd", on);
+    /* ACMD6  */
+    if(!send_cmd(drive, SD_SET_BUS_WIDTH, on ? 2 : 0, MCI_RESP, &response))
+        panicf("sd_set_widebus(%d): set_bus_width", on);
+    /* Now that card is widebus make controller aware */
+    if (on) {
+        MCI_CLOCK(drive) |= MCI_CLOCK_WIDEBUS;
+    } else {
+        MCI_CLOCK(drive) &= ~MCI_CLOCK_WIDEBUS;
+    }
+}
+
+
 #define MCI_FULLSPEED     (MCI_CLOCK_ENABLE | MCI_CLOCK_BYPASS)     /* MCLK   */
 #define MCI_HALFSPEED     (MCI_CLOCK_ENABLE)                        /* MCLK/2 */
 #define MCI_QUARTERSPEED  (MCI_CLOCK_ENABLE | 1)                    /* MCLK/4 */
@@ -362,24 +397,17 @@
     if(!send_cmd(drive, SD_SELECT_CARD, card_info[drive].rca, MCI_RESP, &response))
         return -10;
 
-    /*  Switch to to 4 bit widebus mode  */
-    if(sd_wait_for_tran_state(drive) < 0)
-        return -11;
+    /* Disable card detect pullup, we don't need it */
     /* CMD55 */             /*  Response is requested due to timing issue  */
     if(!send_cmd(drive, SD_APP_CMD, card_info[drive].rca, MCI_RESP, &response))
         return -14;
     /* ACMD42  */
     if(!send_cmd(drive, SD_SET_CLR_CARD_DETECT, 0, MCI_RESP, &response))
         return -15;
-    /* CMD55 */              /*  Response is requested due to timing issue  */
-    if(!send_cmd(drive, SD_APP_CMD, card_info[drive].rca, MCI_RESP, &response))
-        return -12;
-    /* ACMD6  */
-    if(!send_cmd(drive, SD_SET_BUS_WIDTH, 2, MCI_RESP, &response))
-        return -13;
-    /* Now that card is widebus make controller aware */
-    MCI_CLOCK(drive) |= MCI_CLOCK_WIDEBUS;
 
+    /*  Switch to to 4 bit widebus mode  */
+    sd_set_widebus_mode(IF_MD2(drive,) 1);
+
     /*
      * enable bank switching
      * without issuing this command, we only have access to 1/4 of the blocks
@@ -596,15 +624,17 @@
 
     while (1)
     {
-        if(!send_cmd(drive, SD_SEND_STATUS, card_info[drive].rca, MCI_RESP,
-                    &response))
-            return -1;
+        int ret = send_cmd(drive, SD_SEND_STATUS, card_info[drive].rca,
+                           MCI_RESP, &response);
 
-        if (((response >> 9) & 0xf) == SD_TRAN)
+        if (ret && ((response >> 9) & 0xf) == SD_TRAN)
             return 0;
 
-        if(TIME_AFTER(current_tick, timeout))
+        if(TIME_AFTER(current_tick, timeout)) {
+            if (!ret)
+                return -1;
             return -2;
+        }
 
         if (TIME_AFTER(current_tick, next_yield))
         {
@@ -690,6 +720,7 @@
     bool aligned = !((uintptr_t)buf & (CACHEALIGN_SIZE - 1));
 
     mutex_lock(&sd_mtx);
+    sd_transfers[drive]++;
     sd_enable(true);
     led(true);
 
@@ -724,7 +755,7 @@
         if(write)
             clean_dcache_range(buf, count * SECTOR_SIZE);
         else
-            dump_dcache_range(buf, count * SECTOR_SIZE);
+            invalidate_dcache();
     }
 
     while(count)
@@ -853,9 +884,12 @@
             count -= transfer;
             loops = 0;  /* reset errors counter */
         }
-        else if(loops++ > PL180_MAX_TRANSFER_ERRORS)
+        else {
+            sd_transfer_errors[drive]++;
+            if(loops++ > PL180_MAX_TRANSFER_ERRORS)
                 panicf("SD Xfer %s err:0x%x Disk%d", (write? "write": "read"),
                                                   transfer_error[drive], drive);
+        }
     }
 
 sd_transfer_error:
@@ -874,10 +908,35 @@
     return ret;
 }
 
+#define VERIFY_READ 1
+
 int sd_read_sectors(IF_MD2(int drive,) unsigned long start, int count,
                      void* buf)
 {
-    return sd_transfer_sectors(IF_MD2(drive,) start, count, buf, false);
+    int ret;
+
+    ret = sd_transfer_sectors(IF_MD2(drive,) start, count, buf, false);
+
+#ifdef VERIFY_READ
+    if (ret) /* read failed, no point in verifying? */
+        return ret;
+
+    while (count) {
+        int transfer = count;
+        if(transfer > UNALIGNED_NUM_SECTORS)
+            transfer = UNALIGNED_NUM_SECTORS;
+
+        sd_transfer_sectors(IF_MD2(drive,) start, transfer, aligned_buffer, false);
+        if (memcmp(buf, aligned_buffer, transfer * 512) != 0)
+            panicf("sd: read verify failed: sec=%ld n=%d!", start, transfer);
+
+        buf   += transfer * 512;
+        count -= transfer;
+        start += transfer;
+    }
+
+#endif
+    return ret;
 }
 
 int sd_write_sectors(IF_MD2(int drive,) unsigned long start, int count,
@@ -908,7 +967,7 @@
         if (memcmp(buf, aligned_buffer, transfer * 512) != 0) {
             /* try the write again in the hope to repair the damage */
             sd_transfer_sectors(IF_MD2(drive,) saved_start, saved_count, saved_buf, true);
-            panicf("sd: verify failed: sec=%ld n=%d!", start, transfer);
+            panicf("sd: write verify failed: sec=%ld n=%d!", start, transfer);
         }
 
         buf   += transfer * 512;