Re: Bug#986561: linux: Regression in drivers/hid/hid-dr.c causing horizontal D-pad to malfunction on SNES joystick

[Ioan-Adrian Ratiu]

Hi,

On Wed, 14 Apr 2021, Salvatore Bonaccorso <carnil@xxxxxxxxxx> 
wrote:
> Hi Ioan-Adrian, 
>
> On Wed, Apr 07, 2021 at 02:47:24PM +0200, Alessandro Grassi 
> wrote: 
> > Source: linux Severity: normal Tags: upstream X-Debbugs-Cc: 
> > alessandro@xxxxxxxx  Greetings,  I am encountering the issue 
> > described in this thread[1], using a gamepad identified as 
> > "DragonRise" with USB ID 0079:0011.   The joypad works as 
> > intended except for the D-pad: up and down are detected in 
> > jstest (though misinterpreted: the input graph shows the points 
> > in the left up/down corners instead of the center), the left 
> > and right buttons are completely ignored.   Running 
> > 'input-events' shows events 0/127 and 255/127 on up and down 
> > respectively, nothing at all on left and right.   I was able to 
> > identify that the misbehaviour was caused by this commit[2] on 
> > the kernel source tree. To determine this I have rebuilt the 
> > Debian kernel using hid-dr.c from the previous commit[3] and 
> > loaded hid-dr.ko manually, with which the gamepad worked as 
> > intended. I have replaced the file again with the one from the 
> > breaking commit iself ([2]) and the behaviour was again broken. 
> > Furthermore, to confirm that that was the breaking commit, I 
> > have commented line 315 (the input mapping one in the struct) 
> > from the current Debian source tree and rebuilt it, the joypad 
> > works as it should.   Regards, Alessandro  [1]: 
> > https://retropie.org.uk/forum/topic/25657/controler-issue-no-left-and-right-not-working-at-all 
> > [2]: 
> > https://github.com/torvalds/linux/commit/e15944099870f374ca7efc62f98cf23ba272ef43 
> > [3]: 
> > https://github.com/torvalds/linux/commit/313726cad3b68039c8e4dcad5a2840a0d375678c 
>
> A user in Debian reported that e15944099870 ("HID: hid-dr: add 
> input mapping for axis selection") introduced a regression, 
> described above. 
>
> Does this ring some bell to you? 

Unfortunately no and I do not have the HW to test anymore.

It is possible that change introduced a regression on newer 
"DragonRise" gamepads and maybe that mapping logic needs to be a 
bit more complex, depending on the HW differences.

Sorry I can't be more helpful,
Adrian

> Regards,
> Salvatore