(was: drm/ast: Fix potential NULL-pointer read during atomic mode setting) The CRTC's modesetting code in ast requires the format of the primary plane's framebuffer. There's currently a segmentation fault if the framebuffer is set to NULL. This happens when disabling the display during suspend. Patch 1 moves the modesetting code behind a test for the framebuffer in atomic_flush(). It returns if the framebuffer is NULL. This fixes the segmentation fault in a simple and back-portable way. The rest of the patchset addresses problems in the code where access between plane and CRTC state is convoluted and hard to follow. With the changes applied, the atomic_check() functions of primary plane and CRTC set the necessary state that is later used by atomic_flush(). Configurations without framebuffer cannot be rejected because this breaks drm_framebuffer_remove(). Instead accept them and switch off the screen to avoid garbage output. Patch 2 implements this logic for the primary plane. Patches 3 to 5 implement atomic_check() for planes and introduce struct ast_crtc_state. In patches 6 and 7, the atomic_check() functions of CRTC and primary plane set display mode and framebuffer format in the AST CRTC state; and atomic_flush() picks up these settings for configuring the mode. The patchset has been tested by running the fbdev console, Gnome, and Weston on an AST1100 chipset. Gnome's display has been suspended multiple times to verify the bugfix. v3: * start anew with a patch series * put bugfix into atomic_flush() * cleanup mode and framebuffer references in modesetting v2: * do an atomic check for plane * reject invisible primary planes Thomas Zimmermann (7): drm/ast: Move modesetting code to CRTC's atomic_flush() drm/ast: Enable and disable screen in primary-plane functions drm/ast: Clean up arguments of register functions drm/ast: Add plane atomic_check() functions drm/ast: Introduce struct ast_crtc_state drm/ast: Store VBIOS mode info in struct ast_crtc_state drm/ast: Store primary-plane format in struct ast_crtc_state drivers/gpu/drm/ast/ast_drv.h | 11 ++ drivers/gpu/drm/ast/ast_mode.c | 276 ++++++++++++++++++++------------- 2 files changed, 176 insertions(+), 111 deletions(-) -- 2.23.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
