kernel/linux.git/drivers/gpu/drm/drm_dumb_buffers.c, branch linux-7.0.y

drm: include drm_print.h where needed

2025-10-31T08:34:52+00:00

There are a gazillion files that depend on drm_print.h being indirectly included via drm_buddy.h, drm_mm.h, or ttm/ttm_resource.h. In preparation for removing those includes, explicitly include drm_print.h where needed. Cc: Thomas Zimmermann Reviewed-by: Thomas Zimmermann Signed-off-by: Jani Nikula Link: https://lore.kernel.org/r/5fe67395907be33eb5199ea6d540e29fddee71c8.1761734313.git.jani.nikula@intel.com

drm/dumb-buffers: Provide helper to set pitch and size

2025-09-29T11:57:43+00:00

Add drm_modes_size_dumb(), a helper to calculate the dumb-buffer scanline pitch and allocation size. Implementations of struct drm_driver.dumb_create can call the new helper for their size computations. There is currently quite a bit of code duplication among DRM's memory managers. Each calculates scanline pitch and buffer size from the given arguments, but the implementations are inconsistent in how they treat alignment and format support. Later patches will unify this code on top of drm_mode_size_dumb() as much as possible. drm_mode_size_dumb() uses existing 4CC format helpers to interpret the given color mode. This makes the dumb-buffer interface behave similar the kernel's video= parameter. Current per-driver implementations again likely have subtle differences or bugs in how they support color modes. The dumb-buffer UAPI is only specified for known color modes. These values describe linear, single-plane RGB color formats or legacy index formats. Other values should not be specified. But some user space still does. So for unknown color modes, there are a number of known exceptions for which drm_mode_size_dumb() calculates the pitch from the bpp value, as before. All other values work the same but print an error. v6: - document additional use cases for DUMB_CREATE2 in TODO list (Tomi) - fix typos in documentation (Tomi) v5: - check for overflows with check_mul_overflow() (Tomi) v4: - use %u conversion specifier (Geert) - list DRM_FORMAT_Dn in UAPI docs (Geert) - avoid dmesg spamming with drm_warn_once() (Sima) - add more information about bpp special case (Sima) - clarify parameters for hardware alignment - add a TODO item for DUMB_CREATE2 v3: - document the UAPI semantics - compute scanline pitch from for unknown color modes (Andy, Tomi) Signed-off-by: Thomas Zimmermann Reviewed-by: Tomi Valkeinen Reviewed-by: Tomi Valkeinen Link: https://lore.kernel.org/r/20250821081918.79786-3-tzimmermann@suse.de

drm/dumb-buffers: Sanitize output on errors

2025-09-29T11:57:43+00:00

The ioctls MODE_CREATE_DUMB and MODE_MAP_DUMB return results into a memory buffer supplied by user space. On errors, it is possible that intermediate values are being returned. The exact semantics depends on the DRM driver's implementation of these ioctls. Although this is most-likely not a security problem in practice, avoid any uncertainty by clearing the memory to 0 on errors. Signed-off-by: Thomas Zimmermann Reviewed-by: Tomi Valkeinen Link: https://lore.kernel.org/r/20250821081918.79786-2-tzimmermann@suse.de

drm: remove dumb_destroy callback

2023-02-10T11:19:27+00:00

Not used by any driver any more. Signed-off-by: Christian König Reviewed-by: Thomas Zimmermann Tested-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/20230126102814.8722-2-christian.koenig@amd.com

drm: Don't export the drm_gem_dumb_destroy() function

2021-01-05T05:20:25+00:00

The drm_gem_dumb_destroy() isn't used in drivers, don't export it. Signed-off-by: Laurent Pinchart Reviewed-by: Daniel Vetter

drm: drop use of drmP.h in drm/*

2019-05-27T16:07:03+00:00

The use of the drmP.h header file is deprecated. Remove use from all files in drm/* so people do not look there and follow a bad example. Build tested allyesconfig,allmodconfig on x86, arm etc. Including alpha that is as always more challenging than the rest. Signed-off-by: Sam Ravnborg Acked-by: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Sean Paul Cc: David Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20190526173535.32701-8-sam@ravnborg.org

Merge tag 'drm-misc-next-2018-06-27' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

2018-06-28T03:29:07+00:00

drm-misc-next for 4.19: Cross-subsystem Changes: devicetree documentation dt-bindings defintions for sun8i (Jernej Skrabec) Core Changes: Consider drivers setting DRIVER_ATOMIC as atomic (Eric Anholt) Improvements for in-kernel clients (Noralf Trønnes) Export and rename drm_crtc_port_mask() (Jernej Skrabec) Driver Changes: v3d: Add looking for GPU scheduler jobs management (Eric Anholt) Add Ilitek ILI9881c panel driver(Maxime Ripard) rockchip: vop: fixup linebuffer mode calc error (Sandy Huang) tinydrm: new driver for ILI9341 display panels (David Lechner) sun4i: Add TCON TOP driver (Jernej Skrabec) Signed-off-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20180628010018.GA10929@juma

drm: Make ioctls available for in-kernel clients

2018-06-25T14:20:14+00:00

Make ioctl wrappers for functions that will be used by the in-kernel API. The following functions are touched: - drm_mode_create_dumb_ioctl() - drm_mode_destroy_dumb_ioctl() - drm_mode_addfb() - drm_mode_rmfb() Signed-off-by: Noralf Trønnes Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180618141739.48151-4-noralf@tronnes.org

drm/dumb-buffers: Integer overflow in drm_mode_create_ioctl()

2018-05-16T15:56:06+00:00

There is a comment here which says that DIV_ROUND_UP() and that's where the problem comes from. Say you pick: args->bpp = UINT_MAX - 7; args->width = 4; args->height = 1; The integer overflow in DIV_ROUND_UP() means "cpp" is UINT_MAX / 8 and because of how we picked args->width that means cpp < UINT_MAX / 4. I've fixed it by preventing the integer overflow in DIV_ROUND_UP(). I removed the check for !cpp because it's not possible after this change. I also changed all the 0xffffffffU references to U32_MAX. Signed-off-by: Dan Carpenter Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180516140026.GA19340@mwanda

drm/dumb-buffers: Add defaults for .dumb_map_offset and .dumb_destroy

2017-07-29T11:51:44+00:00

Almost everyone did end up using GEM as bo, so this adds defaults for the drm_driver.dumb_destroy and drm_driver.dumb_map_offset callbacks. Signed-off-by: Noralf Trønnes Reviewed-by: Eric Anholt Reviewed-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/1500837417-40580-3-git-send-email-noralf@tronnes.org