I don't think my previous email made it through majordomo's filters, so
trying again.
On 23/01/2019 13:05, Diego Veralli wrote:
Hello,
I've been experiencing issues with a Sony Dualshock controller, which
causes a divide_error in dualshock4_parse_report, using the official
Sony dongle (USB 054c:0ba0).
Kernel: Linux version 4.20.0+ (d@debian-desk2) (gcc version 8.2.0
(Debian 8.2.0-14)) #7 SMP Tue Jan 22 23:02:31 CET 2019. Attached
.config of kernel used under qemu to
debug the issue.
Same problem in the default Debian kernel: Linux version
4.19.0-1-amd64 (debian-kernel@xxxxxxxxxxxxxxxx) (gcc version 8.2.0
(Debian 8.2.0-13)) #1 SMP Debian 4.19.12-1 (2018-12-22)
I can confirm I've had this issue at least since 4.17, but probably
before that as well. I've been running Debian testing and following
along with the updates, no package upgrade has made any difference on
the issue.
What happens is:
1. I turn on the controller (all fine at this point, the controller works)
2. I turn off the controller
3. I turn on the controller again
At this point the computer freezes completely. I've reproduced the
issue under qemu and I can see the freeze causes a panic:
(gdb) bt
#0 delay_tsc (__loops=3696029) at arch/x86/lib/delay.c:79
#1 0xffffffff81060782 in panic (fmt=<optimized out>) at kernel/panic.c:305
#2 0xffffffff8101d8da in oops_end (flags=<optimized out>,
regs=<optimized out>, signr=<optimized out>)
at arch/x86/kernel/dumpstack.c:352
#3 oops_end.cold () at arch/x86/kernel/dumpstack.c:331
#4 0xffffffff8101a4ac in do_trap_no_signal (error_code=<optimized
out>, regs=<optimized out>, str=<optimized out>,
trapnr=<optimized out>, tsk=<optimized out>) at arch/x86/kernel/traps.c:211
#5 do_trap (trapnr=<optimized out>, signr=8, str=<optimized out>,
regs=0xffff88807da03c78, error_code=0, sicode=1,
addr=0xffffffff8178f5a9 <dualshock4_parse_report+233>) at
arch/x86/kernel/traps.c:250
#6 0xffffffff8101a82b in do_error_trap (regs=<optimized out>,
error_code=<optimized out>, str=<optimized out>,
trapnr=<optimized out>, signr=<optimized out>, sicode=<optimized
out>, addr=0xffffffff8178f5a9 <dualshock4_parse_report+233>)
at arch/x86/kernel/traps.c:277
#7 0xffffffff8101ab7e in do_divide_error (regs=0xffff88807da03c78,
error_code=0) at arch/x86/kernel/traps.c:288
#8 0xffffffff81c00b84 in divide_error () at arch/x86/entry/entry_64.S:970
#9 0xffff88807c858000 in ?? ()
#10 0xffff88807ceb0e28 in ?? ()
#11 0x0000000000000015 in irq_stack_union ()
#12 0xffff88807ceb0fb0 in ?? ()
#13 0xffff88807ceb0fd0 in ?? ()
#14 0xffff88807c7f3000 in ?? ()
#15 0x000000000000004c in irq_stack_union ()
#16 0x00000000ffffdb84 in ?? ()
#17 0x0000000000000000 in ?? ()
(gdb)
If I break on divide_error I see the following backtrace:
(gdb) bt
#0 0xffffffff81c00b70 in divide_error () at
arch/x86/entry/entry_64.S:813
#1 0xffffffff8178f5a9 in dualshock4_parse_report
(sc=0xffff88807c772e28, rd=0xffff88807c8ac000 "\001\205{}\177\b",
size=<optimized out>) at drivers/hid/hid-sony.c:1018
#2 0x0000000000000000 in ?? ()
The issue *never* happens the first time I turn on the controller.
Only after turning it off and on again (ironic I suppose?)
The code in question is the following:
int calib_data = mult_frac(calib->sens_numer,
raw_data - calib->bias,
calib->sens_denom);
It seems sens_denom is 0 some times after reconnecting. I've worked
around it with a small change to set calib_data to 0 when sens_denom
is 0, but I've no idea what side effects this change could have eg.
leave the controller in a badly calibrated state.
The issue *only* occurs when I enable Dualshock support in the Steam
client (https://store.steampowered.com/). When this is set, Steam
enables additional features in the controller to set light bar
intensity, colour, etc... Connecting, disconnecting, and reconnecting
the controller without running Steam does *not* cause the issue.
There aren't many userspace applications using the full set of
features of the Sony ds4 dongle so this may be why only Steam triggers
it. I've submitted a bug report
(https://github.com/ValveSoftware/steam-for-linux/issues/6050) but the
Steam devs consider this a kernel issue.
I've reproduced this on 3 physical machines and also qemu/kvm. I've
also tested two different Dualshock controllers. The only thing I've
not been able to test is a second Sony dongle, in case mine is
defective, but I did lend it to a friend who runs Windows and he
reported no issues using the dongle with Steam.
Thanks
Diego
