linux-kernel - Re: [PATCH] Input: psmouse - add resync_on

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Date: Mon, 12 Feb 2024 14:57:08 -0600
From: Jonathan Denose <jdenose@...omium.org>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: LKML <linux-kernel@...r.kernel.org>, jefferymiller@...gle.com, 
	Jonathan Denose <jdenose@...gle.com>, Raul Rangel <rrangel@...omium.org>, linux-input@...r.kernel.org
Subject: Re: [PATCH] Input: psmouse - add resync_on_resume dmi check

Sure thing!

Attached is the dmesg output with the i8042.debug option and without
the change in this patch.

On Fri, Feb 9, 2024 at 1:02 PM Dmitry Torokhov
<dmitry.torokhov@...il.com> wrote:
>
> On Wed, Feb 07, 2024 at 10:39:03AM -0600, Jonathan Denose wrote:
> > Hi Dmitry,
> >
> > Thanks for your reply.
> >
> > On Tue, Feb 6, 2024 at 4:04 PM Dmitry Torokhov
> > <dmitry.torokhov@...il.com> wrote:
> > >
> > > Hi Jonathan,
> > >
> > > On Thu, Nov 02, 2023 at 07:52:47AM -0500, Jonathan Denose wrote:
> > > > Some elantech touchpads consistently fail after resuming from
> > > > suspend at sanity_check in elantech_packet_check_v4. This means
> > > > the touchpad is completely unusable after suspend resume.
> > > >
> > > > With different permutations of i8042 nomux, nopnp, reset, and noloop
> > > > kernel options enabled, and with crc_enabled the touchpad fails in
> > > > the same way.
> > > >
> > > > Resyncing the touchpad after receiving the
> > > > PACKET_UNKNOWN/PSMOUSE_BAD_DATA return code allows the touchpad to
> > > > function correctly on resume. The touchpad fails to reconnect with
> > > > the serio reconnect no matter how many times it retries, so this
> > > > change skips over that retry sequence and goes directly to resync.
> > >
> > > Why can't we do this in elantech_reconnect()? I am sure we can make it
> > > simpler and more robust than what the generic handler is trying to do
> > > with polling and everything.
> > >
> > > Thanks.
> > >
> > > --
> > > Dmitry
> >
> > I am fine with anything that would be simpler and more robust, though
> > I'm not sure how to implement what you are describing.
> >
> > Are you suggesting that in this PSMOUSE_BAD_DATA case, instead of
> > using psmouse_set_state and psmouse_queue_work to call
> > psmouse->reconnect (which calls elantech_reconnect)?
>
> No. From the description it sounds like the device sends wrong/extra
> data right after resume. I think you can handle it in
> elantech_reconnect() method by draining the buffer or issuing poll
> request or something similar.
>
> Can you post the i8042 data stream that happens on suspend/resume?
> Toggling i8042.debug option will cause the driver to dump the data to
> dmesg.
>
> Thanks.
>
> --
> Dmitry

View attachment "i8042_suspend_resume_dmesg.txt" of type "text/plain" (261030 bytes)