On Wed, Sep 16, 2015 at 5:48 AM, Xinliang Liu xinliang.liu@linaro.org wrote:
On 16 September 2015 at 02:25, Rob Herring robh@kernel.org wrote: Hi Rob, thanks a lot for reply:-)
On 09/15/2015 04:37 AM, Xinwei Kong wrote:
If you config DRM_HISI_FBDEV optional, this patch will only support fbdev mode while also supporting double buffer.
This is a lot of duplicated code from CMA fbdev. Is double buffering the only reason why CMA fbdev can't be used or are there some other constraints?
Yes, double buffering is the main reason we rewrite our own fbdev. CMA fbdev only create one buffer. But we need at least double buffer for running Android with fbdev.
Double buffering in fbdev has always been a hack, so I'm guessing that is not a feature that should be added here.
If so, I think it is hard to be accepted for my cma fbdev patch to support multi buffer. This early week, I have sent a cma fbdev patch for supporting this. The subject is "[PATCH] drm/cma-helper: Add multi buffer support for cma fbdev". We do have a strong will to support this feature. I described the reason in the patch. Please take a look for me. Thank you very much.
fwiw, drm_gralloc has support for kms. Currently it is expected to be paired w/ a mesa gpu driver, which might not work for everyone, but I suppose the display part of it could be extracted out for a gralloc.kms.so for pure sw rendering.. that might be a better approach.
http://git.android-x86.org/?p=platform/hardware/drm_gralloc.git
BR, -R
-Xinliang
Rob
Signed-off-by: Xinliang Liu xinliang.liu@linaro.org Signed-off-by: Xinwei Kong kong.kongxinwei@hisilicon.com Signed-off-by: Andy Green andy.green@linaro.org Signed-off-by: Jiwen Qi qijiwen@hisilicon.com Signed-off-by: Yu Gong gongyu@hisilicon.com
drivers/gpu/drm/hisilicon/Kconfig | 13 + drivers/gpu/drm/hisilicon/Makefile | 3 +- drivers/gpu/drm/hisilicon/hisi_drm_connector.c | 4 + drivers/gpu/drm/hisilicon/hisi_drm_drv.c | 9 + drivers/gpu/drm/hisilicon/hisi_drm_dsi.c | 15 + drivers/gpu/drm/hisilicon/hisi_drm_fb.h | 5 + drivers/gpu/drm/hisilicon/hisi_drm_fbdev.c | 395 +++++++++++++++++++++++++ drivers/gpu/drm/hisilicon/hisi_drm_fbdev.h | 24 ++ 8 files changed, 467 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.c create mode 100644 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.h
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