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

From: [email-masked] (Javier Martinez Canillas)
Date: Fri, 27 Mar 2015 20:21:26 +0100

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]>

Best regards,
Javier