lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

usb-storage: Fix devices that cannot handle 32k transfers

Browse Source 
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>
This commit is contained in:
Doug Maxey
2007-12-05 23:36:45 -06:00
committed by Greg Kroah-Hartman
parent b9e13ac30f
commit 33abc04f04
3 changed files with 20 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/usb/storage/scsiglue.c
View File

@@ -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