On Wed, 01 Apr 2015 20:05:46 +0200 Ulf Brosziewski <ulf.brosziew...@t-online.de> wrote:
> Hi, > > there might be a problem. The Linux driver for that touchpad type also > accepts "debounce packets", which have the same format as for the > non-crc version. I have no idea whether that is correct and if those > packets do occur in practice, but if they do they wouldn't pass this > version of sync() (byte 3 would be 0x02 then). > You are right. I haven't had issues so far with debounce packets missing but I obviously only have a very small sample size so there is that. Since the debounce packet is ignored anyways I don't know if it matters that it is thrown out early. Although if it didn't matter there probably wouldn't even be a debounce packet? We could allow byte 3 to pass if its value after the check is 0x02 but that kind of defeats the purpose of the integrity check I guess. Fortunately the values of debounce and head packets match up for non crc elantech v3 touchpads. I don't think there is an elegant way to solve this problem because pms_sync_elantech_v3 is called before the packet is complete and you need the whole packet to check if it is a debounce packet. To solve this we would have to do somthing similar to the linux driver by only checking complete packets.
