Re: [PATCH 1/1] Input - alps: Fix button reporting on the V2 Alps protocol

["Pali Rohár" <pali.rohar@gmail.com>]

On Thursday 30 July 2015 16:28:39 Pali Rohár wrote:
> On Thursday 30 July 2015 16:18:47 Hans de Goede wrote:
> > Hi,
> > 
> > On 30-07-15 16:11, Pali Rohár wrote:
> > >On Thursday 30 July 2015 15:51:25 Hans de Goede wrote:
> > >>Hi Chandler,
> > >>
> > >>On 29-07-15 22:45, cpaul@redhat.com wrote:
> > >>>From: Stephen Chandler Paul <cpaul@redhat.com>
> > >>>
> > >>>The data concerning which buttons on the touchpad are held down or not
> > >>>are in the fourth packet we receive from the mouse, not the first.
> > >>>
> > >>>Signed-off-by: Stephen Chandler Paul <cpaul@redhat.com>
> > >>>---
> > >>>  drivers/input/mouse/alps.c | 6 +++---
> > >>>  1 file changed, 3 insertions(+), 3 deletions(-)
> > >>>
> > >>>diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
> > >>>index 113d6f1..e2f9b25 100644
> > >>>--- a/drivers/input/mouse/alps.c
> > >>>+++ b/drivers/input/mouse/alps.c
> > >>>@@ -254,9 +254,9 @@ static void alps_process_packet_v1_v2(struct psmouse *psmouse)
> > >>>  	/* Non interleaved V2 dualpoint has separate stick button bits */
> > >>>  	if (priv->proto_version == ALPS_PROTO_V2 &&
> > >>>  	    priv->flags == (ALPS_PASS | ALPS_DUALPOINT)) {
> > >>>-		left |= packet[0] & 1;
> > >>>-		right |= packet[0] & 2;
> > >>>-		middle |= packet[0] & 4;
> > >>>+		left |= packet[3] & 1;
> > >>>+		right |= packet[3] & 2;
> > >>>+		middle |= packet[3] & 4;
> > >>>  	}
> > >>>
> > >>>  	alps_report_buttons(dev, dev2, left, right, middle);
> > >>
> > >>Thanks for taking a look at the recordings, but the above patch is wrong,
> > >>if you look slightly higher in the lps_process_packet_v1_v2() function there
> > >>is this:
> > >>
> > >>if (priv->proto_version == ALPS_PROTO_V1) {
> > >>...
> > >>} else {
> > >>	left = packet[3] & 1;
> > >>	right = packet[3] & 2;
> > >>	middle = packet[3] & 4;
> > >>}
> > >>
> > >>So with your patch for the devices in question the entire code flow
> > >>becomes:
> > >>
> > >>	left = packet[3] & 1;
> > >>	right = packet[3] & 2;
> > >>	middle = packet[3] & 4;
> > >>	left |= packet[3] & 1;
> > >>	right |= packet[3] & 2;
> > >>	middle |= packet[3] & 4;
> > >>
> > >>Which is not really helpful for the devices for which I added
> > >>commit 92bac83dd:
> > >>
> > >>https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/input/mouse/alps.c?id=92bac83dd79e60e65c475222e41a992a70434beb
> > >>
> > >>and will cause these devices to regress.
> > >>
> > >>Since Hans de Bruin's laptop is a Dell Latitude D430 and I saw
> > >>the same problem and tested my patch on a Dell Latitude D630,
> > >>it seems the use of the low bits of packet[0] to report the
> > >>trackpoint buttons separately when the touchpad is active is
> > >>a Dell specific thing, so I believe that a patch to only
> > >>activate this code block on Dell's is the right solution for
> > >>the regression Douglas is seeing.
> > >>
> > >>I'll write such a patch and post it shortly.
> > >>
> > >>Regards,
> > >>
> > >>Hans
> > >>
> > >>
> > >>
> > >
> > >Hans, can you check ec and e7 registers if are same or if they differs?
> > 
> > As Benjamin already pointed out Douglas' touchpad matches this
> > line in alps.c :
> > 
> > { { 0x22, 0x02, 0x14 }, 0x00, { ALPS_PROTO_V2, 0xff, 0xff, ALPS_PASS | ALPS_DUALPOINT } },      /* Dell Latitude D600 */
> > 
> > This is a full match
> 
> No, this is not full match. It just check e7, not ec. This is reason why
> I asked for both ec and e7 registers of all affected machines.
> 

Douglas already sent e7 and ec regs:
[    6.617471] psmouse serio1: alps: E7 report: 22 02 14
[    6.656974] psmouse serio1: alps: EC report: 10 00 64

Can you post ec regs from your tested Dell machine?

> > and note the "Dell" in the comment after the line,
> > so it seems that going by the registers is not good enough here, whereas
> > doing a vendor check is actually quite easy, so the patch I just
> > send.
> > 
> 
> If registers are different, then I think it is good idea to check for
> them. I do not like vendor checks in such device driver unless we know
> that there is some special vendor code/bug in firmware which cause it...
> 
> > Regards,
> > 
> > Hans
> > 
> > 
> 

-- 
Pali Rohár
pali.rohar@gmail.com
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