Re: [PATCH v2 2/3] input: alps: For protocol V3, do not process data when last packet's bit7 is set

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On Wed, Oct 15, 2014 at 08:28:59PM +0200, Pali Rohár wrote:
> On Wednesday 15 October 2014 20:17:40 Dmitry Torokhov wrote:
> > On Wed, Oct 15, 2014 at 08:06:45PM +0200, Pali Rohár wrote:
> > > On Wednesday 15 October 2014 19:55:24 Dmitry Torokhov wrote:
> > > > Hi Pali,
> > > > 
> > > > On Fri, Oct 03, 2014 at 03:51:12PM +0200, Pali Rohár wrote:
> > > > > Sometimes laptops with closed lid receive invalid ALPS
> > > > > protocol V3 packets with last bit7 set.
> > > > > 
> > > > > This happens on Dell Latitude laptops and it looks like
> > > > > it is BIOS bug. Probably EC does not correctly split
> > > > > keyboard and touchpad PS/2 data and when laptop lid is
> > > > > closed it adds 0xFF packet into touchpad PS/2 data.
> > > > 
> > > > Is it always 0xff or do you see different values with the
> > > > 7th bit set? Also, the "bad data" - does is always stop
> > > > on the 6th byte of the data stream or the "real" 6th byte
> > > > comes after the bad one?
> > > > 
> > > > Thanks.
> > > 
> > > In this case stream is:
> > > 
> > > 0 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5 ...
> > > V V V V V X V V V V V X V V V V V X ...
> > > 
> > > number packet position in buffer, V means that packet at
> > > specified position in buffer is valid (and also all previous
> > > packets in buffer are valid), X means packet at position is
> > > invalid.
> > > 
> > > It means that alps driver receive 5 valid packets and after
> > > that one is invalid. And again it receive 5 valid and last
> > > invalid...
> > > 
> > > I looked into my logs and X was always 0xFF.
> > 
> > OK, then I think we should change the test to explicitly look
> > for 0xff when returning PSMOUSE_PACKET_FULL.
> > 
> > Thanks.
> 
> Tommy, this patch was originally written by you. (here is)

Hmm, if that was originally done by Tommy I'd need his signed-off-by on
the patch please.

Thanks.

-- 
Dmitry
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