From: Xinliang Liu <xinliang....@linaro.org>
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 at linaro.org>
[s.christ at phytec.de: Picking patch from
https://lkml.org/lkml/2015/9/14/188]
Signed-off-by: Stefan Christ <s.christ at phytec.de>
---
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 fc35731..56cf34d 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -106,6 +106,14 @@ 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 5075fae..be66042 100644
--- a/drivers/gpu/drm/drm_fb_cma_helper.c
+++ b/drivers/gpu/drm/drm_fb_cma_helper.c
@@ -27,6 +27,12 @@
#define DEFAULT_FBDEFIO_DELAY_MS 50
+#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];
@@ -389,7 +395,7 @@ int drm_fbdev_cma_create_with_funcs(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);
--
1.9.1
