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Subject[PATCH] sd.c
The below does two things:
(i) do not try to spin up a CF reader without media
(ii) be careful when asking for the cache parameters mode page

[do not ask for this page when no media are present:
it is meaningless, and some devices react badly if we do;
check the reply so that we do not read past the end of the reply;
first give a small transport length - some USB devices are unhappy
if we ask for more than they provide]

Andries


--- /linux/2.5/linux-2.5.56/linux/drivers/scsi/sd.c Thu Jan 2 14:32:08 2003
+++ sd.c Sun Jan 12 01:50:53 2003
@@ -79,7 +79,7 @@
u8 media_present;
u8 write_prot;
unsigned WCE : 1; /* state of disk WCE bit */
- unsigned RCD : 1; /* state of disk RCD bit */
+ unsigned RCD : 1; /* state of disk RCD bit, unused */
};

static LIST_HEAD(sd_devlist);
@@ -217,7 +217,7 @@
block = SCpnt->request->sector;
this_count = SCpnt->request_bufflen >> 9;

- SCSI_LOG_HLQUEUE(1, printk("sd_command_init: disk=%s, block=%llu, "
+ SCSI_LOG_HLQUEUE(1, printk("sd_init_command: disk=%s, block=%llu, "
"count=%d\n", disk->disk_name, (unsigned long long)block, this_count));

if (!sdp || !sdp->online ||
@@ -809,9 +809,22 @@
if (media_not_present(sdkp, SRpnt))
return;

- /* Look for devices that return NOT_READY.
- * Issue command to spin up drive for these cases. */
- if (the_result && SRpnt->sr_sense_buffer[2] == NOT_READY) {
+ if (the_result == 0)
+ break; /* all is well now */
+
+ /*
+ * If manual intervention is required, or this is an
+ * absent USB storage device, a spinup is meaningless.
+ */
+ if (SRpnt->sr_sense_buffer[2] == NOT_READY &&
+ SRpnt->sr_sense_buffer[12] == 4 /* not ready */ &&
+ SRpnt->sr_sense_buffer[13] == 3)
+ break; /* manual intervention required */
+
+ /*
+ * Issue command to spin up drive when not ready
+ */
+ if (SRpnt->sr_sense_buffer[2] == NOT_READY) {
unsigned long time1;
if (!spintime) {
printk(KERN_NOTICE "%s: Spinning up disk...",
@@ -839,7 +852,7 @@
} while(time1);
printk(".");
}
- } while (the_result && spintime &&
+ } while (spintime &&
time_after(spintime_value + 100 * HZ, jiffies));

if (spintime) {
@@ -851,80 +864,6 @@
}

/*
- * sd_read_cache_type - called only from sd_init_onedisk()
- */
-static void
-sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
- struct scsi_request *SRpnt, unsigned char *buffer) {
-
- unsigned char cmd[10];
- int the_result, retries;
-
- retries = 3;
- do {
-
- memset((void *) &cmd[0], 0, 10);
- cmd[0] = MODE_SENSE;
- cmd[1] = 0x08; /* DBD */
- cmd[2] = 0x08; /* current values, cache page */
- cmd[4] = 128; /* allocation length */
-
-
- memset((void *) buffer, 0, 24);
- SRpnt->sr_cmd_len = 0;
- SRpnt->sr_sense_buffer[0] = 0;
- SRpnt->sr_sense_buffer[2] = 0;
-
- SRpnt->sr_data_direction = SCSI_DATA_READ;
- scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
- 128, SD_TIMEOUT, SD_MAX_RETRIES);
-
- the_result = SRpnt->sr_result;
- retries--;
-
- } while (the_result && retries);
-
- if (the_result) {
- if(status_byte(the_result) == CHECK_CONDITION
- && (SRpnt->sr_sense_buffer[0] & 0x70) == 0x70
- && (SRpnt->sr_sense_buffer[2] & 0x0f) == ILLEGAL_REQUEST
- /* The next are ASC 0x24 ASCQ 0x00: Invalid field in CDB */
- && SRpnt->sr_sense_buffer[12] == 0x24
- && SRpnt->sr_sense_buffer[13] == 0x00) {
- printk(KERN_NOTICE "SCSI device %s: cache data unavailable\n", diskname);
- } else {
- printk(KERN_ERR "%s : MODE SENSE failed.\n"
- "%s : status = %x, message = %02x, host = %d, driver = %02x \n",
- diskname, diskname,
- status_byte(the_result),
- msg_byte(the_result),
- host_byte(the_result),
- driver_byte(the_result)
- );
- if (driver_byte(the_result) & DRIVER_SENSE)
- print_req_sense("sd", SRpnt);
- else
- printk(KERN_ERR "%s : sense not available. \n", diskname);
-
- printk(KERN_ERR "%s : assuming drive cache: write through\n", diskname);
- }
- sdkp->WCE = 0;
- sdkp->RCD = 0;
- } else {
- const char *types[] = { "write through", "none", "write back", "write back, no read (daft)" };
- int ct = 0;
- int offset = buffer[3] + 4; /* offset to start of mode page */
-
- sdkp->WCE = (buffer[offset + 2] & 0x04) == 0x04;
- sdkp->RCD = (buffer[offset + 2] & 0x01) == 0x01;
-
- ct = sdkp->RCD + 2*sdkp->WCE;
-
- printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n", diskname, types[ct]);
- }
-}
-
-/*
* read disk capacity - called only in sd_init_onedisk()
*/
static void
@@ -1102,11 +1041,12 @@

static int
sd_do_mode_sense6(struct scsi_device *sdp, struct scsi_request *SRpnt,
- int modepage, unsigned char *buffer, int len) {
+ int dbd, int modepage, unsigned char *buffer, int len) {
unsigned char cmd[8];

memset((void *) &cmd[0], 0, 8);
cmd[0] = MODE_SENSE;
+ cmd[1] = dbd;
cmd[2] = modepage;
cmd[4] = len;

@@ -1115,6 +1055,8 @@
SRpnt->sr_sense_buffer[2] = 0;
SRpnt->sr_data_direction = SCSI_DATA_READ;

+ memset((void *) buffer, 0, len);
+
scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
len, SD_TIMEOUT, SD_MAX_RETRIES);

@@ -1135,7 +1077,7 @@
* We have to start carefully: some devices hang if we ask
* for more than is available.
*/
- res = sd_do_mode_sense6(sdp, SRpnt, 0x3F, buffer, 4);
+ res = sd_do_mode_sense6(sdp, SRpnt, 0, 0x3F, buffer, 4);

/*
* Second attempt: ask for page 0
@@ -1143,13 +1085,13 @@
* Sense Key 5: Illegal Request, Sense Code 24: Invalid field in CDB.
*/
if (res)
- res = sd_do_mode_sense6(sdp, SRpnt, 0, buffer, 4);
+ res = sd_do_mode_sense6(sdp, SRpnt, 0, 0, buffer, 4);

/*
* Third attempt: ask 255 bytes, as we did earlier.
*/
if (res)
- res = sd_do_mode_sense6(sdp, SRpnt, 0x3F, buffer, 255);
+ res = sd_do_mode_sense6(sdp, SRpnt, 0, 0x3F, buffer, 255);

if (res) {
printk(KERN_WARNING
@@ -1163,6 +1105,65 @@
}
}

+/*
+ * sd_read_cache_type - called only from sd_init_onedisk()
+ */
+static void
+sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
+ struct scsi_request *SRpnt, unsigned char *buffer) {
+ struct scsi_device *sdp = sdkp->device;
+ int len = 0, res;
+
+ const int dbd = 0x08; /* DBD */
+ const int modepage = 0x08; /* current values, cache page */
+
+ /* cautiously ask */
+ res = sd_do_mode_sense6(sdp, SRpnt, dbd, modepage, buffer, 4);
+
+ if (res == 0) {
+ /* that went OK, now ask for the proper length */
+ len = buffer[0] + 1;
+ if (len > 128)
+ len = 128;
+ res = sd_do_mode_sense6(sdp, SRpnt, dbd, modepage, buffer, len);
+ }
+
+ if (res == 0 && buffer[3] + 6 < len) {
+ const char *types[] = {
+ "write through", "none", "write back",
+ "write back, no read (daft)"
+ };
+ int ct = 0;
+ int offset = buffer[3] + 4; /* start of mode page */
+
+ sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
+ sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
+
+ ct = sdkp->RCD + 2*sdkp->WCE;
+
+ printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n",
+ diskname, types[ct]);
+ } else {
+ if (res == 0 ||
+ (status_byte(res) == CHECK_CONDITION
+ && (SRpnt->sr_sense_buffer[0] & 0x70) == 0x70
+ && (SRpnt->sr_sense_buffer[2] & 0x0f) == ILLEGAL_REQUEST
+ /* ASC 0x24 ASCQ 0x00: Invalid field in CDB */
+ && SRpnt->sr_sense_buffer[12] == 0x24
+ && SRpnt->sr_sense_buffer[13] == 0x00)) {
+ printk(KERN_NOTICE "%s: cache data unavailable\n",
+ diskname);
+ } else {
+ printk(KERN_ERR "%s: asking for cache data failed\n",
+ diskname);
+ }
+ printk(KERN_ERR "%s: assuming drive cache: write through\n",
+ diskname);
+ sdkp->WCE = 0;
+ sdkp->RCD = 0;
+ }
+}
+
/**
* sd_init_onedisk - called the first time a new disk is seen,
* performs disk spin up, read_capacity, etc.
@@ -1208,15 +1209,20 @@
sdkp->device->sector_size = 512;
sdkp->media_present = 1;
sdkp->write_prot = 0;
+ sdkp->WCE = 0;
+ sdkp->RCD = 0;

sd_spinup_disk(sdkp, disk->disk_name, SRpnt, buffer);
- sd_read_cache_type(sdkp, disk->disk_name, SRpnt, buffer);

if (sdkp->media_present)
sd_read_capacity(sdkp, disk->disk_name, SRpnt, buffer);

if (sdp->removable && sdkp->media_present)
sd_read_write_protect_flag(sdkp, disk->disk_name, SRpnt, buffer);
+ /* without media there is no reason to ask;
+ moreover, some devices react badly if we do */
+ if (sdkp->media_present)
+ sd_read_cache_type(sdkp, disk->disk_name, SRpnt, buffer);

SRpnt->sr_device->ten = 1;
SRpnt->sr_device->remap = 1;
-
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