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 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?

-- 
Pali Rohár
pali.rohar@gmail.com
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