Re: usb-storage, error reading the last 8 sectors, regression in 2.6.25-rc7

[Boaz Harrosh <bharrosh@panasas.com>]

Alan Stern wrote:
> On Tue, 1 Apr 2008, Matthew Dharm wrote:
> 
>> On Tue, Apr 01, 2008 at 10:28:52AM -0400, Alan Stern wrote:
>>> On Tue, 1 Apr 2008, Oliver Neukum wrote:
>>>
>>>> Am Dienstag, 1. April 2008 03:58:31 schrieb Alan Stern:
>>>>> Nevertheless, it's clear that the problem has nothing to do with the 
>>>>> USB stack.  The real source of the problem lies in the device itself, 
>>>>> for reporting a bogus error when in fact nothing went wrong.  That may 
>>>>> also explain why you don't always see the problem -- sometimes the 
>>>>> device works the way it ought to.
>>>> Reminds me of the devices that can read the last sector but only if it is read
>>>> by itself. Do you reckon this device may have the "opposite" quirk?
>>> Could be something like that.
>> Didn't I see some SCSI patches go by to implement exactly this change?
>> That is, only read the last sector by itself?
> 
> You are getting the two problems mixed up.  The older problem, which
> the SCSI patche addressed, was that the device would fail when
> accessing the last sector unless the transfer was 1 sector long.
> 
> This problem is different.  When performing an 8-sector read that 
> includes the last sector, the device succeeds.  When performing a 
> 7-sector read starting from the same place (so not including the last 
> sector), the device fails.
> 
> Alan Stern
> 

It is a different problem but it explains why it used to work in previous
kernels. 8-sector been one page.

So it is related. Looks like another black list here. Is there a sysfs
way to disable the last-sector-thing for a usb device?

Boaz