On 02/28/2017 09:42 AM, Javier Martinez Canillas wrote:

Hello Shuah,

The subject line isn't consistent with what's used for exynos_defconfig
changes, please use instead:

ARM: exynos_defconfig: Increase CONFIG_CMA_SIZE_MBYTES to 96

oops - I meant o make it exynos_defconfig

On 02/27/2017 09:23 PM, Shuah Khan wrote:

quoted

Current CMA size of 64 Mbytes is right on the edge of being too small
for some display managers.  With the proposed s5p_mfc patch series that
pre-allocate buffers, when display manager starts, it fails to get GEM
buffers.  Increasing the CMA size to 96 solves the problem.

Change CONFIG_CMA_SIZE_MBYTES to 96 in exynos_defconfig to address the
problem.

As you mention, the problem is when a driver pre-allocates a lot of CMA
memory. So instead of mentioning an in-flight patch series, I would make
the commit message more generic. Something along the following lines:

I thought about making it generic and decided to mention the problem I am
seeing, so there is a context to it. Without this patch, some display
managers will see regression.

Current CMA size is 64 Mbytes, but this may not be enough if different
drivers need to allocate big memory chunks.

For example, the s5p-mfc driver may need to do a pre-allocation of N MiB
to decode a H.264 1080p video, and there won't be enough CMA memory left
for others drivers, like the exynos-drm driver that may need to allocate
GEM buffers for the display manager.

Increasing the CMA size to 96 MiB should be enough for most use cases.

I will add the current problem to throw away section of the patch for more
information.

quoted

Signed-off-by: Shuah Khan <redacted>
Suggested-by: Marek Szyprowski <m.szyprowski@samsung.com>
---

Patch looks good to me though.

Reviewed-by: Javier Martinez Canillas <redacted>

thanks for the review. I will send v2 with your reviewed by tag

Best regards,

-- Shuah