diff options
| author | Aaron Lu <aaron.lu@intel.com> | 2013-01-23 15:09:32 +0800 |
|---|---|---|
| committer | Jeff Garzik <jgarzik@redhat.com> | 2013-01-25 15:36:43 -0500 |
| commit | 6f4c827e68a78731c6c75df69bf7b75b029ec70c (patch) | |
| tree | 5113f12fc6fd5c7e2769aa19c2a1bb59ea647652 /drivers/scsi | |
| parent | 6c7f1e2f12f6f37ddda01180c9e5c407eccce616 (diff) | |
[libata] scsi: no poll when ODD is powered off
When the ODD is powered off, any action the user did to the ODD that
would generate a media event will trigger an ACPI interrupt, so the
poll for media event is no longer necessary. And the poll will also
cause a runtime status change, which will stop the ODD from staying in
powered off state, so the poll should better be stopped.
But since we don't have access to the gendisk structure in LLDs, here
comes the disk_events_disable_depth for scsi device. This field is a
hint set by LLDs to convey information to upper layer drivers. A value
of 0 means media poll is necessary for the device, while values above 0
means media poll is not needed and should better be skipped. So we can
increase its value when we are to power off the ODD in ATA layer and
decrease its value when the ODD is powered on, effectively silence the
media events poll.
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'drivers/scsi')
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 14 | ||||
| -rw-r--r-- | drivers/scsi/sr.c | 10 |
2 files changed, 21 insertions, 3 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index f1bf5aff68e..765398c063c 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2617,3 +2617,17 @@ void scsi_kunmap_atomic_sg(void *virt) kunmap_atomic(virt); } EXPORT_SYMBOL(scsi_kunmap_atomic_sg); + +void sdev_disable_disk_events(struct scsi_device *sdev) +{ + atomic_inc(&sdev->disk_events_disable_depth); +} +EXPORT_SYMBOL(sdev_disable_disk_events); + +void sdev_enable_disk_events(struct scsi_device *sdev) +{ + if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0)) + return; + atomic_dec(&sdev->disk_events_disable_depth); +} +EXPORT_SYMBOL(sdev_enable_disk_events); diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c index 2e8ddd77366..f2884ee9071 100644 --- a/drivers/scsi/sr.c +++ b/drivers/scsi/sr.c @@ -602,9 +602,13 @@ static unsigned int sr_block_check_events(struct gendisk *disk, struct scsi_cd *cd = scsi_cd(disk); unsigned int ret; - scsi_autopm_get_device(cd->device); - ret = cdrom_check_events(&cd->cdi, clearing); - scsi_autopm_put_device(cd->device); + if (atomic_read(&cd->device->disk_events_disable_depth) == 0) { + scsi_autopm_get_device(cd->device); + ret = cdrom_check_events(&cd->cdi, clearing); + scsi_autopm_put_device(cd->device); + } else { + ret = 0; + } return ret; } |