Re: [Bug 1412] Copy from USB1 CF/SM reader stalls, no actual content is read (only directory structure)

[Jens Axboe]

On Fri, Nov 07 2003, Nicolas Mailhot wrote:
> Le ven 07/11/2003 à 09:24, Jens Axboe a écrit :
> > On Wed, Nov 05 2003, Alan Stern wrote:
> 
> > > In any case, it quite likely _does_ point to a driver bug.  But since
> > > sddr09_read_data() was handed this sg entry and didn't change it, if there
> > > is such a bug it must lie in a higher-level driver.  Maybe the scsi layer, 
> > > maybe the block layer, maybe the memory-management system, maybe the file 
> > > system.  That was my original point.
> > 
> > Well, the sg entry looks perfectly valid. And that was my original
> > point :-). And that is why I said it looks like a driver bug, not in
> > upper layers. How much memory did the system that crashed have? If the
> > system has highmem, try testing with scsi_calculate_bounce_limit()
> > unconditionally returning BLK_BOUNCE_HIGH.
> 
> The system has 1 GiB of memory, ie just enough to make stuff like
> radeonfb fail

Try with this debug patch then, does it work now?

===== drivers/scsi/scsi_lib.c 1.77 vs edited =====
--- 1.77/drivers/scsi/scsi_lib.c	Tue Oct 14 09:28:06 2003
+++ edited/drivers/scsi/scsi_lib.c	Fri Nov  7 10:08:52 2003
@@ -1215,6 +1215,7 @@
 
 u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
 {
+#if 0
 	struct device *host_dev;
 
 	if (shost->unchecked_isa_dma)
@@ -1229,6 +1230,9 @@
 	 * hardware have no practical limit.
 	 */
 	return BLK_BOUNCE_ANY;
+#else
+	return BLK_BOUNCE_HIGH;
+#endif
 }
 
 struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)

-- 
Jens Axboe

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