Re: [PATCH v2 6/7] drm/i915/dsi: Replace poking of CHV GPIOs behind the driver's back

[Hans de Goede]

Hi,

On 10/31/23 17:07, Hans de Goede wrote:
> Hi Andy,
> 
> On 10/24/23 18:11, Andy Shevchenko wrote:
>> On Tue, Oct 24, 2023 at 06:57:38PM +0300, Andy Shevchenko wrote:
>>> It's a dirty hack in the driver that pokes GPIO registers behind
>>> the driver's back. Moreoever it might be problematic as simultaneous
>>> I/O may hang the system, see the commit 0bd50d719b00 ("pinctrl:
>>> cherryview: prevent concurrent access to GPIO controllers") for
>>> the details. Taking all this into consideration replace the hack
>>> with proper GPIO APIs being used.
>>
>> Ah, just realised that this won't work if it happens to request to GPIOs with
>> the same index but different communities. I will fix that in v3, but will wait
>> for Hans to test VLV and it might even work in most of the cases on CHV as it
>> seems quite unlikely that the above mentioned assertion is going to happen in
>> real life.
> 
> I have added patches 1-5 to my personal tree + a small debug patch on top
> which logs when soc_exec_opaque_gpio() actually gets called.
> 
> So these patches will now get run every time I run some tests on
> one my tablets.
> 
> I'll get back to you with testing results when I've found a device where
> the new soc_exec_opaque_gpio() actually gets called.
> 
> As for the CHT support, I have not added that to my tree yet, I would
> prefer to directly test the correct/fixed patch.

And I hit the "jackpot" on the first device I tried and the code needed
some fixing to actually work, so here is something to fold into v3 to
fix things: