Den 09.11.2021 10.06, skrev Thomas Zimmermann: > Hi > > Am 08.11.21 um 22:01 schrieb Noralf Trønnes: >> >> >> Den 01.11.2021 15.15, skrev Thomas Zimmermann: >>> Add constants for the maximum size of the shadow-plane surface >>> size. Useful for shadow planes with virtual screen sizes. The >>> current sizes are 4096 scanlines with 4096 pixels each. This >>> seems reasonable for current hardware, but can be increased as >>> necessary. >>> >>> In simpledrm, set the maximum framebuffer size from the constants >>> for shadow planes. Implements support for virtual screen sizes and >>> page flipping on the fbdev console. >>> >>> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> >>> --- >>> drivers/gpu/drm/tiny/simpledrm.c | 9 +++++++-- >>> include/drm/drm_gem_atomic_helper.h | 18 ++++++++++++++++++ >>> 2 files changed, 25 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/tiny/simpledrm.c >>> b/drivers/gpu/drm/tiny/simpledrm.c >>> index e872121e9fb0..e42ae1c6ebcd 100644 >>> --- a/drivers/gpu/drm/tiny/simpledrm.c >>> +++ b/drivers/gpu/drm/tiny/simpledrm.c >>> @@ -2,6 +2,7 @@ >>> #include <linux/clk.h> >>> #include <linux/of_clk.h> >>> +#include <linux/minmax.h> >>> #include <linux/platform_data/simplefb.h> >>> #include <linux/platform_device.h> >>> #include <linux/regulator/consumer.h> >>> @@ -776,6 +777,7 @@ static int simpledrm_device_init_modeset(struct >>> simpledrm_device *sdev) >>> struct drm_display_mode *mode = &sdev->mode; >>> struct drm_connector *connector = &sdev->connector; >>> struct drm_simple_display_pipe *pipe = &sdev->pipe; >>> + unsigned long max_width, max_height; >>> const uint32_t *formats; >>> size_t nformats; >>> int ret; >>> @@ -784,10 +786,13 @@ static int simpledrm_device_init_modeset(struct >>> simpledrm_device *sdev) >>> if (ret) >>> return ret; >>> + max_width = max_t(unsigned long, mode->hdisplay, >>> DRM_SHADOW_PLANE_MAX_WIDTH); >>> + max_height = max_t(unsigned long, mode->vdisplay, >>> DRM_SHADOW_PLANE_MAX_HEIGHT); >>> + >>> dev->mode_config.min_width = mode->hdisplay; >>> - dev->mode_config.max_width = mode->hdisplay; >>> + dev->mode_config.max_width = max_width; >>> dev->mode_config.min_height = mode->vdisplay; >>> - dev->mode_config.max_height = mode->vdisplay; >>> + dev->mode_config.max_height = max_height; >>> dev->mode_config.prefer_shadow_fbdev = true; >>> dev->mode_config.preferred_depth = sdev->format->cpp[0] * 8; >>> dev->mode_config.funcs = &simpledrm_mode_config_funcs; >>> diff --git a/include/drm/drm_gem_atomic_helper.h >>> b/include/drm/drm_gem_atomic_helper.h >>> index 48222a107873..54983ecf641a 100644 >>> --- a/include/drm/drm_gem_atomic_helper.h >>> +++ b/include/drm/drm_gem_atomic_helper.h >>> @@ -22,6 +22,24 @@ int drm_gem_simple_display_pipe_prepare_fb(struct >>> drm_simple_display_pipe *pipe, >>> * Helpers for planes with shadow buffers >>> */ >>> +/** >>> + * DRM_SHADOW_PLANE_MAX_WIDTH - Maximum width of a plane's shadow >>> buffer in pixels >>> + * >>> + * For drivers with shadow planes, the maximum width of the >>> framebuffer is >>> + * usually independent from hardware limitations. Drivers can >>> initialize struct >>> + * drm_mode_config.max_width from DRM_SHADOW_PLANE_MAX_WIDTH. >> >> Why would a driver do that instead of using a value of its own? Is it >> some kind of standardization? > > Exactly. The shadow framebuffer is in system memory, so its size is > arbitrarily large. If each driver sets its own limit, it just fragments > the DRM feature set. There's usually no reason why one driver can have > 4096 pixels and another one just 2048 or even 8192. Setting a constant > harmonizes this among drivers. > > Please note that nothing really depends on this value. Drivers can still > use a different limit if they have to. > >> >>> + */ >>> +#define DRM_SHADOW_PLANE_MAX_WIDTH (1ul << 12) >> >> Please use a decimal number, I'm so slow at doing this in my head that I >> use bash to calculate it for me, which really slows down parsing the >> code. > > Ok. :D > With that fixed: Acked-by: Noralf Trønnes <noralf@xxxxxxxxxxx> > Best regard > Thomas > >> >> Noralf. >> >>> + >>> +/** >>> + * DRM_SHADOW_PLANE_MAX_HEIGHT - Maximum height of a plane's shadow >>> buffer in scanlines >>> + * >>> + * For drivers with shadow planes, the maximum height of the >>> framebuffer is >>> + * usually independent from hardware limitations. Drivers can >>> initialize struct >>> + * drm_mode_config.max_height from DRM_SHADOW_PLANE_MAX_HEIGHT. >>> + */ >>> +#define DRM_SHADOW_PLANE_MAX_HEIGHT (1ul << 12) >>> + >>> /** >>> * struct drm_shadow_plane_state - plane state for planes with >>> shadow buffers >>> * >>> >
