[RFC 03/14] bootsplash: Flush framebuffer after drawing
From: Max Staudt <hidden>
Date: 2017-10-25 12:46:36
Also in:
lkml
Subsystem:
framebuffer core, framebuffer layer, the rest · Maintainers:
Simona Vetter, Helge Deller, Linus Torvalds
Framebuffers with deferred I/O need to be flushed to the screen explicitly, since we use neither the mmap nor the file I/O abstractions that handle this for userspace FB clients. Example: xenfb Some framebuffer drivers implement lazy access to the screen without actually exposing a fbdefio interface - we also match some known ones, currently: - ast - cirrus - mgag200 Signed-off-by: Max Staudt <redacted> Reviewed-by: Oliver Neukum <oneukum@suse.com> --- drivers/video/fbdev/core/bootsplash.c | 2 ++ drivers/video/fbdev/core/bootsplash_internal.h | 1 + drivers/video/fbdev/core/bootsplash_render.c | 32 ++++++++++++++++++++++++++ 3 files changed, 35 insertions(+)
diff --git a/drivers/video/fbdev/core/bootsplash.c b/drivers/video/fbdev/core/bootsplash.c
index 7eb2126c3a31..8f1c1c165401 100644
--- a/drivers/video/fbdev/core/bootsplash.c
+++ b/drivers/video/fbdev/core/bootsplash.c@@ -120,6 +120,8 @@ void bootsplash_render_full(struct fb_info *info) return; bootsplash_do_render_background(info); + + bootsplash_do_render_flush(info); }
diff --git a/drivers/video/fbdev/core/bootsplash_internal.h b/drivers/video/fbdev/core/bootsplash_internal.h
index 41d519d88baa..c0653dd7807b 100644
--- a/drivers/video/fbdev/core/bootsplash_internal.h
+++ b/drivers/video/fbdev/core/bootsplash_internal.h@@ -67,5 +67,6 @@ extern struct splash_priv splash_global; */ void bootsplash_do_render_background(struct fb_info *info); +void bootsplash_do_render_flush(struct fb_info *info); #endif
diff --git a/drivers/video/fbdev/core/bootsplash_render.c b/drivers/video/fbdev/core/bootsplash_render.c
index ceb19c34fd61..460ae0168cb0 100644
--- a/drivers/video/fbdev/core/bootsplash_render.c
+++ b/drivers/video/fbdev/core/bootsplash_render.c@@ -91,3 +91,35 @@ void bootsplash_do_render_background(struct fb_info *info) } } } + + +void bootsplash_do_render_flush(struct fb_info *info) +{ + /* FB drivers using deferred_io (such as Xen) need to sync the + * screen after modifying its contents. When the FB is mmap()ed + * from userspace, this happens via a dirty pages callback, but + * when modifying the FB from the kernel, there is no such thing. + * + * So let's issue a fake fb_copyarea (copying the FB onto itself) + * to trick the FB driver into syncing the screen. + * + * A few DRM drivers' FB implementations are broken by not using + * deferred_io when they really should - we match on the known + * bad ones manually for now. + */ + if (info->fbdefio + || !strcmp(info->fix.id, "astdrmfb") + || !strcmp(info->fix.id, "cirrusdrmfb") + || !strcmp(info->fix.id, "mgadrmfb")) { + struct fb_copyarea area; + + area.dx = 0; + area.dy = 0; + area.width = info->var.xres; + area.height = info->var.yres; + area.sx = 0; + area.sy = 0; + + info->fbops->fb_copyarea(info, &area); + } +}
--
2.12.3