On 10/12/2016 05:11 PM, Shuah Khan wrote: + Fixing Krzysztof Kozlowski address. > Hi Inki, > > On 08/15/2016 10:40 PM, Inki Dae wrote: > >>> >>> okay the very first commit that added IOMMU support >>> introduced the code that rejects non-contig gem memory >>> type without IOMMU. >>> >>> commit 0519f9a12d0113caab78980c48a7902d2bd40c2c >>> Author: Inki Dae <inki.dae@xxxxxxxxxxx> >>> Date: Sat Oct 20 07:53:42 2012 -0700 >>> >>> drm/exynos: add iommu support for exynos drm framework >>> > > I haven't given up on this yet. I am still seeing the following failure: > > Additional debug messages I added: > [ 15.287403] exynos_drm_gem_create_ioctl() 1 > [ 15.287419] exynos_drm_gem_create() flags 1 > > [ 15.311511] [drm:exynos_drm_framebuffer_init] *ERROR* Non-contiguous GEM memory is not supported. > > Additional debug message I added: > [ 15.318981] [drm:exynos_user_fb_create] *ERROR* failed to initialize framebuffer > > This is what happens: > > 1. exynos_drm_gem_create_ioctl() gets called with EXYNOS_BO_NONCONTIG request > 2. exynos_drm_gem_create(0 goes ahead and creates the GEM buffers > 3. exynos_user_fb_create() tries to associate GEM to fb and fails during > check_fb_gem_memory_type() > > At this point, there is no recovery and lightdm fails > > xf86-video-armsoc/src/drmmode_exynos/drmmode_exynos.c assumes contiguous > allocations are not supported in some exynos drm versions: The following > commit introduced this change: > > https://git.linaro.org/arm/xorg/driver/xf86-video-armsoc.git/commitdiff/3be1f6273441fe95dd442f44064387322e16b7e9 > > excerpts from the diff:- if (create_gem->buf_type == ARMSOC_BO_SCANOUT) > - create_exynos.flags = EXYNOS_BO_CONTIG; > - else > - create_exynos.flags = EXYNOS_BO_NONCONTIG; > + > + /* Contiguous allocations are not supported in some exynos drm versions. > + * When they are supported all allocations are effectively contiguous > + * anyway, so for simplicity we always request non contiguous buffers. > + */ > + create_exynos.flags = EXYNOS_BO_NONCONTIG; > > There might have been logic on exynos_drm that forced Contig when it coudn't > support NONCONTIG. At least, that is what this comment suggests. This assumption > doesn't appear to be a good one and not sure if this change was made to fix a bug. > > After the IOMMU support, this assumption is no longer true. Hence, with IOMMU > support, latest kernels have a mismatch with the installed xf86-video-armsoc > > This is what I am running into. This leads to the following question: > > 1. How do we ensure exynos_drm kernel changes don't break user-space > specifically xf86-video-armsoc > 2. This seems to have gone undetected for a while. I see a change in > exynos_drm_gem_dumb_create() that is probably addressing this type > of breakage. Commit 122beea84bb90236b1ae545f08267af58591c21b adds > handling for IOMMU NONCONTIG case. > > Anyway, I am interested in getting the exynos_drm kernel side code > and xf86-video-armsoc in sync to resolve the issue. > > Could you recommend a going forward plan? > > I can submit a patch to xf86-video-armsoc. I am also looking ahead to > see if we can avoid such breaks in the future by keeping kernel and > xf86-video-armsoc in sync. > > thanks, > -- Shuah > -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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