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authorDoug Maxey <dwm@enoyolf.org>2007-12-05 23:36:45 -0600
committerGreg Kroah-Hartman <gregkh@suse.de>2007-12-17 10:47:14 -0800
commit33abc04f0420dceed0ebc2d1094019d3bb2b5c29 (patch)
tree87d8e2c7cf41d6afed4d75c2e3ef113b506541ab /drivers/usb/storage/scsiglue.c
parentb9e13ac30f850313be9232497ff98e90c43bc6b6 (diff)
usb-storage: Fix devices that cannot handle 32k transfers
When a device cannot handle the smallest previously limited transfer size (64 blocks) without stalling, limit the device to the amount of packets that fit in a platform native page. The lowest possible limit is PAGE_CACHE_SIZE, so if the device is ever used on a platform that has larger than 8K pages, you lose unless you can convince the device firmware folks to fix the issue. Cc: Mathew Dharm <mdharm-scsi@one-eyed-alien.net> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Doug Maxey <dwm@austin.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/storage/scsiglue.c')
-rw-r--r--drivers/usb/storage/scsiglue.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 836a34ae6ec..7c9593b7b04 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -114,9 +114,15 @@ static int slave_configure(struct scsi_device *sdev)
* while others have trouble with more than 64K. At this time we
* are limiting both to 32K (64 sectores).
*/
- if ((us->flags & US_FL_MAX_SECTORS_64) &&
- sdev->request_queue->max_sectors > 64)
- blk_queue_max_sectors(sdev->request_queue, 64);
+ if (us->flags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
+ unsigned int max_sectors = 64;
+
+ if (us->flags & US_FL_MAX_SECTORS_MIN)
+ max_sectors = PAGE_CACHE_SIZE >> 9;
+ if (sdev->request_queue->max_sectors > max_sectors)
+ blk_queue_max_sectors(sdev->request_queue,
+ max_sectors);
+ }
/* We can't put these settings in slave_alloc() because that gets
* called before the device type is known. Consequently these