Hello, Kay.
I've played with the patch and the usb stick and it seems to be
generally working. I've made some changes tho.
* The TUR and GET_EVENT results accumulated between clearing
check_events() should be compared, not the ones from single run.
* TUR reporting media change while GET_EVENT doesn't is okay.
* If ignore_get_event is set, kernel media polling can continue
operating using TUR so that userland doesn't have to worry about
working around.
* Flags moved to a separate bitfield var for proper exclusion.
How does this one look?
Thanks.
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 4778e27..ffb173e 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -221,14 +221,33 @@ static unsigned int sr_check_events(struct cdrom_device_info *cdi,
return 0;
events = sr_get_events(cd->device);
+ cd->get_event_changed |= events & DISK_EVENT_MEDIA_CHANGE;
+
+ /*
+ * If earlier GET_EVENT_STATUS_NOTIFICATION and TUR did not agree
+ * for a couple of times in a row. We rely on TUR only for this
+ * likely broken device, to prevent generating incorrect media
+ * changed events for every open().
+ */
+ if (cd->ignore_get_event) {
+ events &= ~DISK_EVENT_MEDIA_CHANGE;
+ goto do_tur;
+ }
+
/*
* GET_EVENT_STATUS_NOTIFICATION is enough unless MEDIA_CHANGE
* is being cleared. Note that there are devices which hang
* if asked to execute TUR repeatedly.
*/
- if (!(clearing & DISK_EVENT_MEDIA_CHANGE))
- goto skip_tur;
+ if (cd->device->changed) {
+ events |= DISK_EVENT_MEDIA_CHANGE;
+ cd->device->changed = 0;
+ cd->tur_changed = true;
+ }
+ if (!(clearing & DISK_EVENT_MEDIA_CHANGE))
+ return events;
+do_tur:
/* let's see whether the media is there with TUR */
last_present = cd->media_present;
ret = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
@@ -242,11 +261,27 @@ static unsigned int sr_check_events(struct cdrom_device_info *cdi,
(scsi_sense_valid(&sshdr) && sshdr.asc != 0x3a);
if (last_present != cd->media_present)
- events |= DISK_EVENT_MEDIA_CHANGE;
-skip_tur:
+ cd->device->changed = 1;
+
if (cd->device->changed) {
events |= DISK_EVENT_MEDIA_CHANGE;
cd->device->changed = 0;
+ cd->tur_changed = true;
+ }
+
+ if (!cd->ignore_get_event) {
+ /* check for spurious changed events from GET_EVENT */
+ if (cd->get_event_changed && !cd->tur_changed) {
+ if (cd->tur_mismatch++ > 8) {
+ sdev_printk(KERN_WARNING, cd->device,
+ "GET_EVENT and TUR disagree continuously, suppress GET_EVENT events\n");
+ cd->ignore_get_event = true;
+ }
+ } else {
+ cd->tur_mismatch = 0;
+ }
+ cd->tur_changed = true;
+ cd->get_event_changed = true;
}
return events;
diff --git a/drivers/scsi/sr.h b/drivers/scsi/sr.h
index e036f1d..f8ea01e 100644
--- a/drivers/scsi/sr.h
+++ b/drivers/scsi/sr.h
@@ -41,6 +41,13 @@ typedef struct scsi_cd {
unsigned readcd_known:1; /* drive supports READ_CD (0xbe) */
unsigned readcd_cdda:1; /* reading audio data using READ_CD */
unsigned media_present:1; /* media is present */
+
+ /* GET_EVENT spurious event handling, block guarantees exclusion */
+ int tur_mismatch; /* nr of get_event TUR mismatches */
+ bool tur_changed:1; /* changed according to TUR */
+ bool get_event_changed:1; /* changed according to GET_EVENT */
+ bool ignore_get_event:1; /* get_event is unreliable, use TUR */
+
struct cdrom_device_info cdi;
/* We hold gendisk and scsi_device references on probe and use
* the refs on this kref to decide when to release them */
--
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