Re: [PATCH 2/2] hid: Don't sign-extend 16-bit values.

[Kai Krakow]

Am Mo., 11. Feb. 2019 um 22:26 Uhr schrieb Kai Krakow :
> Hey Zeb!
> > > > Wine can pick up controllers from udev, either via hidraw or evdev, as
> > > > well as from SDL. As of bd9e130ee, we shouldn't be using signed offsets
> > > > anymore when reporting SDL controllers, so I assumed that your
> > > > controller was coming through hidraw directly.
> > >
> > > Not sure, does the log show this? I'm pretty sure it's going through
> > > SDL because I can apply SDL controller mappings to it through
> > > environment.
> >
> > Log should show this, yes.
> > > > The symptoms you describe imply that anything above 0x6000 (?) is
> > > > somehow wrapping around to negative, though that doesn't necessarily
> > > > make very much sense.
> > >
> > > Indeed, I'm confused too. ;-)
> >
> > Well, it's close to an explanation. INSIDE, which prompted these
> > patches, showed very similar symptoms: the game assumed that the
> > controller had a range of 0-32767, and so mapped 0-16383 to "left" and
> > 16384-32767 to "right", and negative values were interpreted as above
> > 16384 and therefore also "right". Thus the effect was basically the same
> > as you describe, except inverted.
> > > > Can you provide a log with
> > > > +hid,+hidp,+hid_report,+rawinput?
> > >
> > > Sure, I'll do. But please wait, I really need some sleep now, this was
> > > bothering me for a few hours now. ;-)
> > >
> > > Just let me know: Two logs? One with patches reverted and one without?
> >
> > Just without any patches reverted (so with the bug visible) will
> > hopefully be enough.
>
> Here's the log:
> https://gist.github.com/a9b51a975f933482a7125792a66bf3cd

This looks correct:

0022:trace:hid:debug_print_value_cap INPUT Value: 0x1/0x30: ReportId
0, IsAbsolute 1, HasNull 0, Bit Size 16, ReportCount 1, UnitsExp 0,
Units 0, LogicalMin 0, Logical Max 65535, PhysicalMin 0, PhysicalMax
65535 -- StartBit 24/16
0022:trace:hid:debug_print_value_cap INPUT Value: 0x1/0x31: ReportId
0, IsAbsolute 1, HasNull 0, Bit Size 16, ReportCount 1, UnitsExp 0,
Units 0, LogicalMin 0, Logical Max 65535, PhysicalMin 0, PhysicalMax
65535 -- StartBit 40/16
0022:trace:hid:debug_print_value_cap INPUT Value: 0x1/0x33: ReportId
0, IsAbsolute 1, HasNull 0, Bit Size 16, ReportCount 1, UnitsExp 0,
Units 0, LogicalMin 0, Logical Max 65535, PhysicalMin 0, PhysicalMax
65535 -- StartBit 56/16
0022:trace:hid:debug_print_value_cap INPUT Value: 0x1/0x34: ReportId
0, IsAbsolute 1, HasNull 0, Bit Size 16, ReportCount 1, UnitsExp 0,
Units 0, LogicalMin 0, Logical Max 65535, PhysicalMin 0, PhysicalMax
65535 -- StartBit 72/16
0022:trace:hid:debug_print_value_cap INPUT Value: 0x1/0x32: ReportId
0, IsAbsolute 1, HasNull 0, Bit Size 16, ReportCount 1, UnitsExp 0,
Units 0, LogicalMin 0, Logical Max 32767, PhysicalMin 0, PhysicalMax
32767 -- StartBit 88/16
0022:trace:hid:debug_print_value_cap INPUT Value: 0x1/0x35: ReportId
0, IsAbsolute 1, HasNull 0, Bit Size 16, ReportCount 1, UnitsExp 0,
Units 0, LogicalMin 0, Logical Max 32767, PhysicalMin 0, PhysicalMax
32767 -- StartBit 104/16

Confirming with evtest:

Event type 3 (EV_ABS)
   Event code 0 (ABS_X)
     Value      0
     Min   -32768
     Max    32767
     Flat    4095
   Event code 1 (ABS_Y)
     Value      0
     Min   -32768
     Max    32767
     Flat    4095
   Event code 2 (ABS_Z)
     Value      0
     Min        0
     Max     1023
     Fuzz       3
     Flat      63
   Event code 3 (ABS_RX)
     Value      0
     Min   -32768
     Max    32767
     Fuzz     255
     Flat    4095
   Event code 4 (ABS_RY)
     Value      0
     Min   -32768
     Max    32767
     Fuzz     255
     Flat    4095
   Event code 5 (ABS_RZ)
     Value      0
     Min        0
     Max     1023
     Fuzz       3
     Flat      63

Thanks,
Kai