Subject: [RFT PATCHv2] drm/exynos: Enable DP clock to fix display on Exynos5250 and other

From: [email-masked] (Andreas Färber)
Date: Tue, 31 Mar 2015 13:42:32 +0200

Am 27.03.2015 um 20:21 schrieb Javier Martinez Canillas:
> Hello Krzysztof,
> 
> On 03/27/2015 05:08 PM, Krzysztof Kozlowski wrote:
>> After adding display power domain for Exynos5250 in commit
>> 2d2c9a8d0a4f ("ARM: dts: add display power domain for exynos5250") the
>> display on Chromebook Snow and others stopped working after boot.
>>
>> The reason for this suggested Andrzej Hajda: the DP clock was disabled.
>> This clock is required by Display Port and is enabled by bootloader.
>> However when FIMD driver probing was deferred, the display power domain
>> was turned off. This effectively reset the value of DP clock enable
>> register.
>>
>> When exynos-dp is later probed, the clock is not enabled and display is
>> not properly configured:
>>
>> exynos-dp 145b0000.dp-controller: Timeout of video streamclk ok
>> exynos-dp 145b0000.dp-controller: unable to config video
>>
>> Signed-off-by: Krzysztof Kozlowski <[email-masked]>
>> Reported-by: Javier Martinez Canillas <[email-masked]>
>> Fixes: 2d2c9a8d0a4f ("ARM: dts: add display power domain for exynos5250")
>> Cc: <[email-masked]>
>>
>> ---
>>
>> This should fix issue reported by Javier [1][2].
>>
> 
> I tested this patch and does indeed solves both issues I reported
> The exynos-dp probe deferral does not make the display to not be
> working and also disabling and enabling the display with:
> 
> with /sys/devices/platform/exynos-drm/graphics/fb0/blank works.
> 
> Thanks a lot for fixing this issue.
> 
> On an Exynos5250 Snow Chromebook:
> 
> Tested-by: Javier Martinez Canillas <[email-masked]>

Seems to fix Spring Chromebook as well,

Tested-by: Andreas F?rber <[email-masked]>

Thanks a lot,

Andreas

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