Re: [PATCH] Input: ALPS - fix DualPoint flag for 74 03 28 devices

["Pali Rohár" <pali.rohar@gmail.com>]

Ideally this information should be put as a comment into the code. It is
really not obvious.

On Tuesday 27 March 2018 04:37:19 Masaki Ota wrote:
> Hi, 
> 
> We can get OTP page 0 value by EA EA E9 commands, but we cannot get it by EA EA EA E9.
> As far as I remember, Device initialization finish at EA command, then sends EA EA E9 commands.
> In this case we cannot get correct OTP page 0 value.
> So I changed this order. (We can get OTP page 1 value by both of EA F0 F0 E9 and F0 F0 E9.)
> 
> Best Regards,
> Masaki Ota
> -----Original Message-----
> From: Pali Rohár [mailto:pali.rohar@gmail.com] 
> Sent: Monday, March 26, 2018 6:26 AM
> To: 太田 真喜 Masaki Ota <masaki.ota@jp.alps.com>
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>; linux-input@vger.kernel.org; linux-kernel@vger.kernel.org; Aaron Ma <aaron.ma@canonical.com>
> Subject: Re: [PATCH] Input: ALPS - fix DualPoint flag for 74 03 28 devices
> 
> On Tuesday 20 March 2018 11:47:26 Dmitry Torokhov wrote:
> > On Mon, Jan 29, 2018 at 2:51 PM, dmitry.torokhov@gmail.com 
> > <dmitry.torokhov@gmail.com> wrote:
> > > Hi,
> > >
> > > On Thu, Nov 16, 2017 at 07:27:02AM +0000, Masaki Ota wrote:
> > >> Hi, Pali, Aaron,
> > >>
> > >> Current code is correct device setting, previous code is wrong.
> > >> If the trackstick does not work(DUALPOINT flag disable), Device Firmware setting is wrong.
> > >>
> > >> But recently I received the same report from Thinkpad L570 user, and I checked this device and found this device Firmware setting is wrong. Sorry for our mistake.
> > >> Is your laptop L570 ?
> > >>
> > >> I will add code that supports the trackstick for this device.
> > >
> > > Sorry for resurrecting this old thread, I am just trying to 
> > > understand what went wrong here. Is the sequence of "f0 f0 e9" and 
> > > "ea ea e9" is important in getting the correct OTP data and we 
> > > originally got this order wrong? It is not clear from the original 
> > > patch and discussion that this change was intentional.
> > 
> > Could I please get an answer to my question?
> > 
> > Thanks!
> 
> Masaki, this question is for you ↑↑↑
> 
> > >
> > > Thanks.
> > >
> > >>
> > >> Best Regards,
> > >> Masaki Ota
> > >> -----Original Message-----
> > >> From: Pali Rohár [mailto:pali.rohar@gmail.com]
> > >> Sent: Wednesday, November 15, 2017 5:35 PM
> > >> To: 太田 真喜 Masaki Ota <masaki.ota@jp.alps.com>
> > >> Cc: linux-input@vger.kernel.org; linux-kernel@vger.kernel.org; 
> > >> dmitry.torokhov@gmail.com; Aaron Ma <aaron.ma@canonical.com>
> > >> Subject: Re: [PATCH] Input: ALPS - fix DualPoint flag for 74 03 28 
> > >> devices
> > >>
> > >> On Wednesday 15 November 2017 14:34:04 Aaron Ma wrote:
> > >> > There is a regression of commit 4a646580f793 ("Input: ALPS - fix 
> > >> > two-finger scroll breakage"), ALPS device fails with log:
> > >> >
> > >> > psmouse serio1: alps: Rejected trackstick packet from non 
> > >> > DualPoint device
> > >> >
> > >> > ALPS device with id "74 03 28" report OTP[0] data 0xCE after 
> > >> > commit 4a646580f793, after restore the OTP reading order, it 
> > >> > becomes to 0x10 as before and reports the right flag.
> > >> >
> > >> > Fixes: 4a646580f793 ("Input: ALPS - fix two-finger scroll 
> > >> > breakage")
> > >> > Cc: <stable@vger.kernel.org>
> > >> > Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
> > >> > ---
> > >> >  drivers/input/mouse/alps.c | 4 ++--
> > >> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > >> >
> > >> > diff --git a/drivers/input/mouse/alps.c 
> > >> > b/drivers/input/mouse/alps.c index 579b899add26..c59b8f7ca2fc 
> > >> > 100644
> > >> > --- a/drivers/input/mouse/alps.c
> > >> > +++ b/drivers/input/mouse/alps.c
> > >> > @@ -2562,8 +2562,8 @@ static int alps_set_defaults_ss4_v2(struct 
> > >> > psmouse *psmouse,
> > >> >
> > >> >     memset(otp, 0, sizeof(otp));
> > >> >
> > >> > -   if (alps_get_otp_values_ss4_v2(psmouse, 1, &otp[1][0]) ||
> > >> > -       alps_get_otp_values_ss4_v2(psmouse, 0, &otp[0][0]))
> > >> > +   if (alps_get_otp_values_ss4_v2(psmouse, 0, &otp[0][0]) ||
> > >> > +       alps_get_otp_values_ss4_v2(psmouse, 1, &otp[1][0]))
> > >> >             return -1;
> > >> >
> > >> >     alps_update_device_area_ss4_v2(otp, priv);
> > >>
> > >> Masaki Ota, please look at this patch as it partially revert your 
> > >> commit
> > >> 4a646580f793 ("Input: ALPS - fix two-finger scroll breakage"). Something smells here.
> > >>
> > >> --
> > >> Pali Rohár
> > >> pali.rohar@gmail.com
> > >
> > > --
> > > Dmitry
> > 
> > 
> > 
> 
> --
> Pali Rohár
> pali.rohar@gmail.com

-- 
Pali Rohár
pali.rohar@gmail.com