Re: [PATCH v3 0/2] drm: Support framebuffer panning

From: Neil Armstrong
Date: Thu Feb 16 2017 - 11:40:45 EST


On 02/15/2017 05:19 PM, Maxime Ripard wrote:
> Hi,
>
> This is a respin of the previous serie called "Support fast framebuffer
> panning for i.MX6" made by Stefan 6 monthes ago. The imx6 bits have been
> removed, and the comments that were made at that time fixed (hopefully).
>
> Let me know what you think,
> Maxime
>
> Changes from v2:
> - Renamed the CONFIG_DRM_CMA_FBDEV_BUFFER_NUM to
> CONFIG_DRM_FBDEV_OVERALLOC, and changed it for a percentage
> - Moved the overallocation code into the core fbdev helpers to not rely
> on CMA anymore
> - Changed the locks taken by drm_fb_helper_ioctl to the mode_config mutex
> intead of calling drm_modeset_lock_all
> - Don't test against drm_crtc's enabled anymore, but rely on the error
> code of drm_crtc_vblank_get instead
> - Defined drm_fb_helper_ioctl when DRM_FBDEV_EMULATION is not set in
> order to fix a compilation error
> - Don't wait for all CRTC's vblank but only the one given in the ioctl
> argument
>
> Changes from v1:
> - Added drm_fb_helper_ioctl to DRM_FB_HELPER_DEFAULT_OPS
> - Expanded a bit the kerneldoc for drm_fb_helper_ioctl
> - Added some locking to drm_fb_helper_ioctl
> - Checked that the framebuffer is indeed attached before allowing ioctl
> - Added a module parameter to specify the number of framebuffers to
> allocate
>
> Initial cover letter: Support fast framebuffer panning for i.MX6
>
> im currently working on supporting double/tripple buffering for the
> framebuffer emulation on the i.MX6. While working on it I noticed that the
> mainline kernel does not support some features in the generic drm
> framebuffer emulation for framebuffer panning and vsync synchronisation.
> They are needed for simple framebuffer applications and some OpenGL
> libraries using double buffering with FBIOPUT_VSCREENINFO,
> FBIO_WAITFORVSYNC and FBIOPAN_DISPLAY.
>
> Stefan Christ (1):
> drm/fb-helper: implement ioctl FBIO_WAITFORVSYNC
>
> Xinliang Liu (1):
> drm/fb-helper: Add multi buffer support for cma fbdev
>
> drivers/gpu/drm/Kconfig | 9 ++++-
> drivers/gpu/drm/drm_fb_helper.c | 73 ++++++++++++++++++++++++++++++++++-
> include/drm/drm_fb_helper.h | 12 +++++-
> 3 files changed, 93 insertions(+), 1 deletion(-)
>
> base-commit: 0879b944c95d65f7523d178d3addaebe84e510ec
>
Hi Maxime,

Just tested these patches on Amlogic GXBB to provide 3D Mali acceleration on framebuffer.

Tested-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>

Thanks,
Neil