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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

drivers/usb/storage/scsiglue.c

+9 −3
Original line number Diff line number Diff line
@@ -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

drivers/usb/storage/unusual_devs.h

+7 −0
Original line number Diff line number Diff line
@@ -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> */

include/linux/usb_usual.h

+4 −1
Original line number Diff line number Diff line
@@ -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 };