Re: [PATCH] platform/x86: int3472: add HP Spectre handshake delay

[Hans de Goede <hansg@kernel.org>]

Hi Alexander,

On 18-Aug-26 12:43, Hans de Goede wrote:
> Hi,
> 
> On 16-Aug-26 22:42, James Alexander wrote:
>> The OVTI08F4 sensor on an HP Spectre x360 14-eu0xxx failed to read its
>> chip ID with error -121 when the existing 45 ms handshake delay was used.
>> Increasing the delay to 150 ms allowed the sensor to probe.
>>
>> Keep the existing delay for other OVTI08F4 systems. Add a reusable
>> handshake-delay field to the discrete-device quirks and set it only for the
>> affected HP Spectre family through DMI matching.
>>
>> Compile-tested against Linux base fd923b32d761. Hardware-tested with the
>> full patch set across 25 consecutive reboots on the affected laptop running
>> Ubuntu 7.0.0-29-generic; the sensor probed successfully on every boot.
>>
>> Signed-off-by: James Alexander <opensource@inspiredexperts.com>
> 
> Thank you for your patch.
> 
> There have been more reports about the 45 ms not being enough of a delay,
> but IIRC I never got around to bumping the delay because even with
> a bigger delay on the laptop in question the probe would still fail
> approx. every 1 out of 10 boots and we got stuck on debugging that.
> 
> And then I dropped the bal on this, sorry.
> 
> See:
> https://bugzilla.redhat.com/show_bug.cgi?id=2333331

Funny after re-reading that bug I see you are one of the reporters
of it, again sorry for dropping the ball on this.

> https://bugzilla.redhat.com/show_bug.cgi?id=2333647

And this is more or less the same thing, but here the sensor is
a hi556. So it looks like the fix is to simply boost the handshake
pin default delay to 200 ms instead of having a model / device
specific quirk, dropping the existing OVTI08F4 quirk.

I'll go and prepare a patch for this and submit it upstream myself.

Regards,

Hans