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Exynos SYSMMU (IOMMU) integration with DT and DMA-mapping subsystem

Javier Martinez Canillas linux-arm-kernel linux-iommu linux-samsung-soc 6 versions – New

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  1. v3 Latest posting 6/60 of 19 patches 0 repliesNew
  2. v3 posting 5/60 of 19 patches 0 repliesSuperseded
  3. v3 posting 4/60 of 19 patches 0 repliesSuperseded
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VersionPostedPatchesRepliesStatus
v3 posting 3/60 of 19 patches0 repliesSuperseded
v3 posting 2/60 of 19 patches0 repliesSuperseded
v3 posting 1/60 of 19 patches0 repliesSuperseded

Patches in v3 posting 6/6 No applies recorded yet

None of the 19 patches the cover letter announces are in this archive.

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Cover letter [PATCH v3 00/19] Exynos SYSMMU (IOMMU) integration with DT and DMA-mapping subsystem

Hello Joonyoung,

Quoted 9 lines · Joonyoung Shim
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I dug further on this issue and found that the cause is that the exynos_mixer driver needs some clocks (CLK_HDMI and CLK_SCLK_HDMI) grabbed by exynos_hdmi to be kept enabled after hdmi_poweroff (drivers/gpu/drm/exynos/exynos_hdmi.c).

Otherwise, any access to mixer device registers leads to an imprecise external abort error. The following change [0] to the Exynos DRM HDMI driver makes the issue to not happen and I can successfully execute:

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# echo 1 > /sys/devices/platform/exynos-drm/graphics/fb0/blank
# echo 0 > /sys/devices/platform/exynos-drm/graphics/fb0/blank

Did you execute this operation repeatedly? Still i get error when i execute this more than twice with your change [0].

You mean that you are seeing the "Power domain power-domain disable failed" message but the system is not crashing or that you are still having the system crash?

I've seen the former when running multiple times but I have not seen the crash when the hdmi clock is not disabled on hdmi_poweroff().

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Thanks.

Best regards,
Javier

Read the cover letter in its thread