On 02/27/2017 05:50 AM, Marek Szyprowski wrote: > Hi Shuah, > > On 2017-02-24 15:23, Shuah Khan wrote: >> On Thu, Feb 23, 2017 at 11:26 PM, Marek Szyprowski >> <m.szyprowski@xxxxxxxxxxx> wrote: >>> On 2017-02-23 22:43, Shuah Khan wrote: >>>> On Tue, Feb 14, 2017 at 12:52 AM, Marek Szyprowski >>>> <m.szyprowski@xxxxxxxxxxx> wrote: >>>>> It turned out that all versions of MFC v6+ hardware doesn't have a strict >>>>> requirement for ALL buffers to be allocated on higher addresses than the >>>>> firmware base like it was documented for MFC v5. This requirement is true >>>>> only for the device and per-context buffers. All video data buffers can >>>>> be >>>>> allocated anywhere for all MFC v6+ versions. Basing on this fact, the >>>>> special DMA configuration based on two reserved memory regions is not >>>>> really needed for MFC v6+ devices, because the memory requirements for >>>>> the >>>>> firmware, device and per-context buffers can be fulfilled by the simple >>>>> probe-time pre-allocated block allocator instroduced in previous patch. >>>>> >>>>> This patch enables support for such pre-allocated block based allocator >>>>> always for MFC v6+ devices. Due to the limitations of the memory >>>>> management >>>>> subsystem the largest supported size of the pre-allocated buffer when no >>>>> CMA (Contiguous Memory Allocator) is enabled is 4MiB. >>>>> >>>>> This patch also removes the requirement to provide two reserved memory >>>>> regions for MFC v6+ devices in device tree. Now the driver is fully >>>>> functional without them. >>>>> >>>>> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> >>>> Hi Marek, >>>> >>>> This patch breaks display manager. exynos_drm_gem_create() isn't happy. >>>> dmesg and console are flooded with >>>> >>>> odroid login: [ 209.170566] [drm:exynos_drm_gem_create] *ERROR* failed to >>>> allo. >>>> [ 212.173222] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 215.354790] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 218.736464] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 221.837128] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 226.284827] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 229.242498] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 232.063150] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 235.799993] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 239.472061] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 242.567465] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 246.500541] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 249.996018] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 253.837272] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 257.048782] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 260.084819] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 263.448611] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 266.271074] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 269.011558] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 272.039066] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 275.404938] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 278.339033] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 281.274751] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 284.641202] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 287.461039] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 291.062011] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 294.746870] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> [ 298.246570] [drm:exynos_drm_gem_create] *ERROR* failed to allocate >>>> buffer. >>>> >>>> I don't think this is an acceptable behavior. It is a regression. >>> >>> This is a really poor bug report... Could you elaborate a bit how to >>> reproduce >>> this? Could you provide your kernel config and information about test >>> environment? >> Yeah. I should have give you more information. My bad. >> >>> I suspect that you use CMA without IOMMU and you have too small global CMA >>> region. >> Yes. I have CMA and using exynos_defconfig. Nothing fancy. I think >> what's happening is s5p_mfc pre-allocates and there is nothing left >> when disaply manager starts requestuing gem buffers. This failure >> happens when systemd kicks off lightdm. >> >>> After this patch MFC driver uses global CMA region instead of the MFC's >>> private >>> ones, so one has to ensure that the global region is large enough. >> This is still a regression since it requires users to take some >> action. I think we need some kind of checks to warn users there isn't >> a large enough CMA region. This is the same config I have been using >> forever and with this patch, it breaks. >> >> Easy to reproduce on odroid-xu4 with HDMI display. You just have to >> boot the system with exynos_defconfig. Display manager will fail when >> it requests buffers. > > That is still a bit strange. MFC pre-allocates 8MiB buffer. The default CMA > global region size is 64MiB, which should be enough for a few display buffers. > It looks that your display manager consumes quite a lot of memory and it > already almost hits the limit from the exynos_defconfig. > > It should be safe to increase default CMA region size to 80MiB or even 96MiB > in the exynos_defconfig to avoid such problem. Increasing CONFIG_CMA_SIZE_MBYTES to 96 in exynos_defconfig worked for me. No more gem buffer allocation errors. I sent in a patch to exynos_defconfig with your Suggested-by thanks, -- Shuah > > Best regards
