Re: [PATCH] sr: update to follow tray status correctly

James Bottomley
2008-02-06T19:02:05Z

On Wed, 2008-02-06 at 17:09 +0000, Daniel Drake wrote:
> Hi James,
>
> James Bottomley wrote:
> > It's been a while with no status on this one, so I corrected the patch
> > based on my original input. The attached is what I think is the best
> > way of doing this (I've replaced the home grown test_unit_ready routine
> > with the SCSI one and updated some of the sense check conditions).
>
> Many thanks for following up on this. The user has not responded to my
> request for him to test your patch, so I decided to try it myself. I'm
> using Linus git as of today, I noticed the patch is merged.
>
> It doesn't work for me. On unpatched 2.6.24, I get the behaviour
> previously described - the ioctl always gives CDS_TRAY_OPEN regardless
> of tray status. On 2.6.24-git which includes your patch, I instead
> always get CDS_DISC_OK. I have confirmed that on 2 systems this is
> because scsi_test_unit_ready() is returning 0.
>
> Before I dig further, does this work for you? I have attached the test
> program I am using.

Heh, you assume I have a CD easily to hand in my testing setup. But,
unfortunately it requires a bit of manual intervention to set up the
state ...

However, I think you're right, the vanilla TUR does eat NOT_READY for
removable media, which CDs are. Does this fix it?

James

---
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 50ba492..1332a5c 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -163,6 +163,29 @@ static void scsi_cd_put(struct scsi_cd *cd)
mutex_unlock(&sr_ref_mutex);
}

+/* identical to scsi_test_unit_ready except that it doesn't
+ * eat the NOT_READY returns for removable media */
+int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr)
+{
+ int retries = MAX_RETRIES;
+ int the_result;
+ u8 cmd[] = {TEST_UNIT_READY, 0, 0, 0, 0, 0 };
+
+ /* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
+ * conditions are gone, or a timeout happens
+ */
+ do {
+ the_result = scsi_execute_req (sdev, cmd, DMA_NONE, NULL,
+ 0, sshdr, SR_TIMEOUT,
+ retries--);
+
+ } while (retries > 0 &&
+ (!scsi_status_is_good(the_result) ||
+ (scsi_sense_valid(sshdr) &&
+ sshdr->sense_key == UNIT_ATTENTION)));
+ return the_result;
+}
+
/*
* This function checks to see if the media has been changed in the
* CDROM drive. It is possible that we have already sensed a change,
@@ -185,8 +208,7 @@ static int sr_media_change(struct cdrom_device_info *cdi, int slot)
}

sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
- retval = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES,
- sshdr);
+ retval = sr_test_unit_ready(cd->device, sshdr);
if (retval || (scsi_sense_valid(sshdr) &&
/* 0x3a is medium not present */
sshdr->asc == 0x3a)) {
@@ -733,10 +755,8 @@ static void get_capabilities(struct scsi_cd *cd)
{
unsigned char *buffer;
struct scsi_mode_data data;
- unsigned char cmd[MAX_COMMAND_SIZE];
struct scsi_sense_hdr sshdr;
- unsigned int the_result;
- int retries, rc, n;
+ int rc, n;

static const char *loadmech[] =
{
@@ -758,23 +778,8 @@ static void get_capabilities(struct scsi_cd *cd)
return;
}

- /* issue TEST_UNIT_READY until the initial startup UNIT_ATTENTION
- * conditions are gone, or a timeout happens
- */
- retries = 0;
- do {
- memset((void *)cmd, 0, MAX_COMMAND_SIZE);
- cmd[0] = TEST_UNIT_READY;
-
- the_result = scsi_execute_req (cd->device, cmd, DMA_NONE, NULL,
- 0, &sshdr, SR_TIMEOUT,
- MAX_RETRIES);
-
- retries++;
- } while (retries < 5 &&
- (!scsi_status_is_good(the_result) ||
- (scsi_sense_valid(&sshdr) &&
- sshdr.sense_key == UNIT_ATTENTION)));
+ /* eat unit attentions */
+ sr_test_unit_ready(cd->device, &sshdr);

/* ask for mode page 0x2a */
rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h
index 81fbc0b..1e144df 100644
--- a/drivers/scsi/sr.h
+++ b/drivers/scsi/sr.h
@@ -61,6 +61,7 @@ int sr_select_speed(struct cdrom_device_info *cdi, int speed);
int sr_audio_ioctl(struct cdrom_device_info *, unsigned int, void *);

int sr_is_xa(Scsi_CD *);
+int sr_test_unit_ready(struct scsi_device *sdev, struct scsi_sense_hdr *sshdr);

/* sr_vendor.c */
void sr_vendor_init(Scsi_CD *);
diff --git a/drivers/scsi/sr_ioctl.c b/drivers/scsi/sr_ioctl.c
index d5cebff..ae87d08 100644
--- a/drivers/scsi/sr_ioctl.c
+++ b/drivers/scsi/sr_ioctl.c
@@ -306,8 +306,7 @@ int sr_drive_status(struct cdrom_device_info *cdi, int slot)
/* we have no changer support */
return -EINVAL;
}
- if (0 == scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES,
- &sshdr))
+ if (0 == sr_test_unit_ready(cd->device, &sshdr))
return CDS_DISC_OK;

if (!cdrom_get_media_event(cdi, &med)) {