linux-kernel - Re: rpi-b-rev2 can't detect hdmi display due to wrong hpd gpio pull in dts

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Message-ID: <b488f43d-2fe3-6e1d-bed0-94ed9d033129@collabora.com>
Date:   Mon, 4 Mar 2019 18:54:00 -0300
From:   Helen Koike <helen.koike@...labora.com>
To:     Eric Anholt <eric@...olt.net>
Cc:     linux-rpi-kernel@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        stefan.wahren@...e.com, linus.walleij@...aro.org, lkundrak@...sk,
        bcm-kernel-feedback-list@...adcom.com, devicetree@...r.kernel.org,
        kernel@...labora.com
Subject: Re: rpi-b-rev2 can't detect hdmi display due to wrong hpd gpio pull
 in dts



On 3/4/19 5:27 PM, Eric Anholt wrote:
> Helen Koike <helen.koike@...labora.com> writes:
> 
>> Hello,
>>
>> I have a rpi-b-rev2 (two holes, 512M) and when I was trying to test vc4
>> driver, the HDMI wans't being detected.
>>
>> So I changed the hpd-gpios from ACTIVE_LOW to ACTIVE_HIGH and now it
>> works correctly. I can see that modeprint from libdrm detects correctly
>> when the display is plugged and when it is unpluggled.
>>
>> So I was wondering if this is just in my board or if there is an error
>> in the dts (which I think it's unlikely).
>>
>> In any case I am dropping this email here in case anyone else see this
>> problem, if you do, try appliying the patch below.
> 
> We even have the GPIO labeled as "HDMI_HPD_P" above, and dt-blob.dts
> agrees.

You are right, I didn't notice it.

> 
> Reviewed-by: Eric Anholt <eric@...olt.net>
> Thanks!  If Stefan doesn't pick this up shortly, I can.
> 

Thanks for reviewing!

Helen