Re: [PATCH 4.19 16/50] gpiolib: acpi: Add gpiolib_acpi_run_edge_events_on_boot option and blacklist

Pavel Machek
2019-09-19T07:46:07Z

[-- Attachment #1: Type: text/plain, Size: 1378 bytes --]

On Wed 2019-09-18 08:18:59, Greg Kroah-Hartman wrote:
> From: Hans de Goede <hdegoede@redhat.com>
>
> commit 61f7f7c8f978b1c0d80e43c83b7d110ca0496eb4 upstream.
>
> Another day; another DSDT bug we need to workaround...
>
> Since commit ca876c7483b6 ("gpiolib-acpi: make sure we trigger edge events
> at least once on boot") we call _AEI edge handlers at boot.
>
> In some rare cases this causes problems. One example of this is the Minix
> Neo Z83-4 mini PC, this device has a clear DSDT bug where it has some copy
> and pasted code for dealing with Micro USB-B connector host/device role
> switching, while the mini PC does not even have a micro-USB connector.
> This code, which should not be there, messes with the DDC data pin from
> the HDMI connector (switching it to GPIO mode) breaking HDMI support.
>
> To avoid problems like this, this commit adds a new
> gpiolib_acpi.run_edge_events_on_boot kernel commandline option, which
> allows disabling the running of _AEI edge event handlers at boot.

So... apparently Windows does _not_ run _AEI edge event handlers at
boot, otherwise Minix would realize that fault.

Would it make sense not to do it by default, either?

Best regards,
Pavel

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]