This patch add a config to support to create multi buffer for cma fbdev. Such as double buffer and triple buffer.
Cma fbdev is convient to add a legency fbdev. And still many Android devices use fbdev now and at least double buffer is needed for these Android devices, so that a buffer flip can be operated. It will need some time for Android device vendors to abondon legency fbdev. So multi buffer for fbdev is needed.
Signed-off-by: Xinliang Liu xinliang.liu@linaro.org --- drivers/gpu/drm/Kconfig | 8 ++++++++ drivers/gpu/drm/drm_fb_cma_helper.c | 8 +++++++- 2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index 1a0a8df..577f790 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -97,6 +97,14 @@ config DRM_KMS_CMA_HELPER help Choose this if you need the KMS CMA helper functions
+config DRM_CMA_FBDEV_BUFFER_NUM + int "Cma Fbdev Buffer Number" + depends on DRM_KMS_CMA_HELPER + default 1 + help + Defines the buffer number of cma fbdev. Default is one buffer. + For double buffer please set to 2 and 3 for triple buffer. + source "drivers/gpu/drm/i2c/Kconfig"
config DRM_TDFX diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c index c19a625..26051b8 100644 --- a/drivers/gpu/drm/drm_fb_cma_helper.c +++ b/drivers/gpu/drm/drm_fb_cma_helper.c @@ -25,6 +25,12 @@ #include <drm/drm_fb_cma_helper.h> #include <linux/module.h>
+#ifdef CONFIG_DRM_CMA_FBDEV_BUFFER_NUM +#define FBDEV_BUFFER_NUM CONFIG_DRM_CMA_FBDEV_BUFFER_NUM +#else +#define FBDEV_BUFFER_NUM 1 +#endif + struct drm_fb_cma { struct drm_framebuffer fb; struct drm_gem_cma_object *obj[4]; @@ -253,7 +259,7 @@ static int drm_fbdev_cma_create(struct drm_fb_helper *helper, bytes_per_pixel = DIV_ROUND_UP(sizes->surface_bpp, 8);
mode_cmd.width = sizes->surface_width; - mode_cmd.height = sizes->surface_height; + mode_cmd.height = sizes->surface_height * FBDEV_BUFFER_NUM; mode_cmd.pitches[0] = sizes->surface_width * bytes_per_pixel; mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);