Re: [PATCH 2/3] HID: valve-index: Reboot headset on system power transitions

[Mario Limonciello]

On 9/11/26 00:54, Greg Kroah-Hartman wrote:
> On Thu, Sep 10, 2026 at 12:02:53PM -0500, Mario Limonciello wrote:
> > The Valve Index HMD stops serving its EDID after the host disables the
> > DisplayPort PHY.  The headset remains powered by its breakout box across
> > suspend and shutdown, so the bad state survives and the next connector
> > detection reports "No EDID read".  The HMD then appears as a synthesized
> > 640x480 display until it is power-cycled.
> >
> > The 64-byte HID output report 0x16 with command 0x01 reboots the headset
> > and restores its EDID service.  Add a device-specific driver which sends
> > this report for system sleep transitions and orderly shutdown while leaving
> > runtime autosuspend alone.
> >
> > Resume a runtime-suspended interface for a shutdown request and restrict
> > the command to the composite interface which declares report 0x16.
> >
> > Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/4333
> > Link: https://github.com/ValveSoftware/SteamVR-for-Linux/issues/939
> > Assisted-by: LLM
> > Co-developed-by: Curtis Vogt <curtis.vogt@xxxxxxxxx>
> > Signed-off-by: Curtis Vogt <curtis.vogt@xxxxxxxxx>
> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> > ---
> >   .../ABI/testing/sysfs-driver-hid-valve-index  |  12 ++
> >   drivers/hid/Kconfig                           |  11 ++
> >   drivers/hid/Makefile                          |   1 +
> >   drivers/hid/hid-ids.h                         |   1 +
> >   drivers/hid/hid-valve-index.c                 | 142 ++++++++++++++++++
> >   5 files changed, 167 insertions(+)
> >   create mode 100644 Documentation/ABI/testing/sysfs-driver-hid-valve-index
> >   create mode 100644 drivers/hid/hid-valve-index.c
> >
> > diff --git a/Documentation/ABI/testing/sysfs-driver-hid-valve-index b/Documentation/ABI/testing/sysfs-driver-hid-valve-index
> > new file mode 100644
> > index 0000000000000..47d8c26b1eace
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-driver-hid-valve-index
> > @@ -0,0 +1,12 @@
> > +What:		/sys/bus/hid/devices/<bus>:<vid>:<pid>.<n>/reboot
> > +Date:		October 2026
> > +Contact:	linux-input@xxxxxxxxxxxxxxx
> > +Description:
> > +		Writing a boolean true value reboots the Valve Index headset to
> > +		recover its EDID service. Writing a boolean false value has no
> > +		effect. This file is write-only.
>
> Shouldn't this just be a debugfs file?  Making it a sysfs file seems
> "risky" as it's not a normal operation.

Yeah I guess that makes sense.

> > +		The Valve Index is a composite HID device. The reboot command is
> > +		only supported by the interface that provides the headset's 64-byte
> > +		output report. Writing true to this file on another interface fails
> > +		with -ENODEV.
>
> Why would it be present on "another interface'?  That feels wrong.
>
> thanks,
>
> greg k-h