Commit 33abc04f authored by Doug Maxey's avatar Doug Maxey Committed by Greg Kroah-Hartman
Browse files

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: default avatarDoug Maxey <dwm@austin.ibm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent b9e13ac3
......@@ -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
......
......@@ -376,6 +376,13 @@ UNUSUAL_DEV( 0x04b0, 0x0417, 0x0100, 0x0100,
US_SC_DEVICE, US_PR_DEVICE, NULL,
US_FL_FIX_CAPACITY),
/* Reported by Doug Maxey (dwm@austin.ibm.com) */
UNUSUAL_DEV( 0x04b3, 0x4001, 0x0110, 0x0110,
"IBM",
"IBM RSA2",
US_SC_DEVICE, US_PR_CB, NULL,
US_FL_MAX_SECTORS_MIN),
/* BENQ DC5330
* Reported by Manuel Fombuena <mfombuena@ya.com> and
* Frank Copeland <fjc@thingy.apana.org.au> */
......
......@@ -48,7 +48,10 @@
US_FLAG(IGNORE_DEVICE, 0x00000800) \
/* Don't claim device */ \
US_FLAG(CAPACITY_HEURISTICS, 0x00001000) \
/* sometimes sizes is too big */
/* sometimes sizes is too big */ \
US_FLAG(MAX_SECTORS_MIN,0x00002000) \
/* Sets max_sectors to arch min */
#define US_FLAG(name, value) US_FL_##name = value ,
enum { US_DO_ALL_FLAGS };
......
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