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. -- Pali Rohár pali.rohar@xxxxxxxxx
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