Re: 2.6.33 bugs (USBFS, Intel graphic)

From: Markus Rechberger
Date: Fri Feb 26 2010 - 23:05:50 EST


On Sat, Feb 27, 2010 at 4:56 AM, Greg KH <greg@xxxxxxxxx> wrote:
> On Sat, Feb 27, 2010 at 04:42:53AM +0100, Markus Rechberger wrote:
>> * http://lkml.org/lkml/2010/2/19/192
>> .6.32-stable review patch.  If anyone has any objections, please let us know.
>>
>> ------------------
>> From: Greg KH <greg@xxxxxxxxx>
>>
>> commit d4a4683ca054ed9917dfc9e3ff0f7ecf74ad90d6 upstream.
>>
>> We need to only copy the data received by the device to userspace, not
>> the whole kernel buffer, which can contain "stale" data.
>>
>> Thanks to Marcus Meissner for pointing this out and testing the fix.
>>
>> Reported-by: Marcus Meissner <meissner@xxxxxxx>
>> Tested-by: Marcus Meissner <meissner@xxxxxxx>
>> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
>> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
>>
>>
>> this patch breaks isochronous USBFS support, please revert that patch!
>>
>> http://sundtek.de/images/tvtime-bildfehler.jpg
>>
>> with the patch reverted:
>> http://sundtek.de/images/tvtime-working.png
>>
>> * Intel graphic flickers now
>
> That is very strange.  What userspace program is using usbfs for video
> feeds?  And why would it be relying on the invalid data on the end of an
> urb?
>

there are 2 userspace videowrapper available for linux and freebsd
which do videoprocessing in userland rather than in kernelspace.
Well isochronous works slightly different than BULK transfer (which I
guess was tested)
urb->iso_frame_desc[i].actual_length
each microframe has it's own length field for ISO.

Markus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/