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

Krzysztof Kozlowski k.kozlowski at samsung.com
Fri May 1 02:14:55 PDT 2015

2015-05-01 1:50 GMT+09:00 Olof Johansson <olof at lixom.net>:
> On Thu, Apr 30, 2015 at 9:40 AM, Javier Martinez Canillas
> <javier.martinez at collabora.co.uk> wrote:
>> Hello Olof,
>> On 04/30/2015 05:57 PM, Olof Johansson wrote:
>>> On Thu, Apr 30, 2015 at 8:44 AM, Kevin Hilman <khilman at kernel.org> wrote:
>>>> Krzysztof Kozlowski <k.kozlowski at samsung.com> writes:
>>>>>>> This should fix issue reported by Javier [1][2].
>>>>>>> Tested on Chromebook Snow (Exynos 5250). More testing would be great,
>>>>>>> especially on other Exynos 5xxx products.
>>>>>> I hoped to try this on my exynos5 boards, but it doesn't seem to apply
>>>>>> to linux-next or to Linus' master branch.
>>>>>> Are there some other dependencies here?
>>>>> It is already applied:
>>>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1c363c7cccf64128087002b0779986ad16aff6dc
>>>> Er, yup.  That would explain it. ;)
>>>> Sorry for the noise,
>>> Well, noise or not, Exynos is still broken in mainline and was broken
>>> on -next for so long in different ways that bisecting it is a futile
>>> exercise in frustration.
>>> It doesn't seem to show up with a trivial boot using only ramdisk, but
>>> when booting a real distro from disk, it certainly does.
>>> For example:
>>> http://arm-soc.lixom.net/bootlogs/mainline/v4.1-rc1-56-g3d99e3f/pi-arm-exynos_defconfig.html
>>> Disabling CONFIG_DRM makes it boot reliably.
>>> Arndale doesn't show it for me, but it also doesn't have working graphics.
>> Both Exynos5250 and Exynos5420 had similar issues and $subject is the fix
>> for 5250 while 5420 is fixed by my "ARM: dts: Make DP a consumer of DISP1
>> power domain on Exynos5420" patch that was posted a long time ago. I have
>> pinged Kukjin several times about this patch and he said that he will pick
>> it this weekend [0].
>> It is indeed very frustrating how many Exynos patches seems to be falling
>> through the crack, even important fixes like these ones that allow boards
>> to boot again.
>> Kevin suggested that Krzysztof could collect and queue patches [1] to help
>> Kukjin and start acting as a co-maintatiner which I think it's a very good
>> idea and Krzysztof already did for some patches during the 4.1 cycle.

Yes, I did. It turned quite well, most of the patches I collected were
pulled :) .

> Yes, that's a much needed improvement. I suggest starting out by
> collecting critical fixes like these, and we'd be happy to merge them
> directly if going through Kukjin will add latency.
> Krzysztof, if you can, make sure you get a PGP key setup and start
> collecting signatures from kernel developers.

Sure, I'll start right away!

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