On 2015년 07월 31일 09:32, Krzysztof Kozlowski wrote:

On 28.07.2015 17:51, Joonyoung Shim wrote:

...

This is simplest solution about reported problem[1]. It's no problem to clear channel only when iommu is enabled, if we consider that we cannot recognize iommu errors when iommu is disabled and it have been valid until now. But this cannot be nice solution.

[1] https://lkml.org/lkml/2015/7/21/404

Reported-by: Krzysztof Kozlowski k.kozlowski@samsung.com Signed-off-by: Joonyoung Shim jy0922.shim@samsung.com

I tested this patch on my Odroid XU3-Lite with hardkernel u-boot and it fixes the booting hang. Thanks!

Thanks for the test.

This patch fixes the booting hang issue but I'm not sure of this patch being able to resolve the issue clearly.

In relation to this, I tried to resolve the issue using sub driver stuff, which makes a probe callback for fimd sub driver to be called after crtc and connector binding is completed.

I guessed that with this, ACLK_200_DISP1 would be enabled by connector driver - mipi dsi or panel driver. However, the moment that the clock is enabled is at mode setting operation so the patch doesn't resolve the issue because the callback I added will be called before mode setting operation.

So the solution we could try would be to make FIMD driver to enable relevant clock in case of Exynos5422 SoC. However, this way is also not clear to me because it is required for additional device tree binding.

Anyway, I merged below patch so let's resolve this issue with more generic way later.

P.s., I removed the patch which incurred the kernel hang issue from exynos-drm-fixes, and moved it to exynos-drm-next with below patch so now there must be no any problem with exynos-drm-fixes.

Thanks, Inki Dae

The test was not thorough - only booting and without any display output (HDMI).

Best regards, Krzysztof

...

---

v2: add Reported-by.

drivers/gpu/drm/exynos/exynos_drm_fimd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c index 8d362b9..337af02 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c +++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c @@ -956,7 +956,8 @@ static int fimd_bind(struct device *dev, struct device *master, void *data) if (ctx->display) exynos_drm_create_enc_conn(drm_dev, ctx->display);

• fimd_clear_channels(ctx->crtc);

• if (is_drm_iommu_supported(drm_dev))

• fimd_clear_channels(ctx->crtc);
  
  

  ret = drm_iommu_attach_device(drm_dev, dev); if (ret)

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