Re: [PATCH v2 2/2] usb: dwc3: gadget: fix high speed multiplier setting

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On 7/8/2022, Michael Grzeschik wrote:
> Cc: Thinh.Nguyen@synopsys.com
>
> On Fri, Jul 08, 2022 at 02:45:30PM +0200, Greg KH wrote:
>> On Mon, Jul 04, 2022 at 04:18:12PM +0200, Michael Grzeschik wrote:
>>> For High-Speed Transfers the prepare_one_trb function is calculating 
>>> the
>>> multiplier setting for the trb based on the length parameter of the trb
>>> currently prepared. This assumption is wrong. For trbs with a sg list,
>>> the length of the actual request has to be taken instead.
>>>
>>> Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
>>> ---
>>> v1 -> v2: - added refactor patch before this patch
>>>           - using req->request.length as condition value
>>
>> Does this need to be backported to older kernels or is it ok for
>> 5.20-rc1?
>
> We can add this line to the patch.
>
> Fixes: 40d829fb2ec6 ("usb: dwc3: gadget: Correct ISOC DATA PIDs for 
> short packets")
>
> I would say this could be backported.
>
> Thinh?

Hi Michael,

Since you have the refactoring patch prior to this, it's a bit difficult 
to backport cleanly without rewriting the patch.

It would be nice to be able to backport fixes. But for this particular 
fix, I don't think will affect too many users. Not many application 
would use SG for simply 3KB or less requests. (Note that periodic ep can 
only transfer up to 3KB/interval in HS). Typically a page size is 4KB, 
and I don't think SG is needed.

Anyway, I think Greg already picked up your patches. Thanks for the fix!

BR,
Thinh