On Thu, Apr 30, 2015 at 8:44 AM, Kevin Hilman [off-list ref] wrote:

Krzysztof Kozlowski [off-list ref] writes:

quoted

2015-04-30 2:31 GMT+09:00 Kevin Hilman [off-list ref]:

quoted

Krzysztof Kozlowski [off-list ref] writes:

quoted

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 <redacted>
Reported-by: Javier Martinez Canillas <redacted>
Fixes: 2d2c9a8d0a4f ("ARM: dts: add display power domain for exynos5250")
Cc: <redacted>

---

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

363c7cccf64128087002b0779986ad16aff6dc

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.


-Olof