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? > + */ > +#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. 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 > * >
