| Message ID | 20250218142542.438557-1-tzimmermann@suse.de |
|---|---|
| Headers | show |
| Series | drm/dumb-buffers: Fix and improve buffer-size calculation | expand |
Hi Am 18.02.25 um 20:32 schrieb Geert Uytterhoeven: [...] >> + args->bpp); >> + fallthrough; >> + case 12: >> + case 15: >> + case 30: /* see drm_gem_afbc_get_bpp() */ >> + case 10: > Perhaps keep them sorted numerically? The first block comes from the afbc helper; the second block from Mesa; hence the odd order. I'll reorder and comment each case individually. > >> + case 64: /* used by Mesa */ >> + pitch = args->width * DIV_ROUND_UP(args->bpp, SZ_8); >> + break; >> + } >> + } >> + >> + if (!pitch || pitch > U32_MAX) >> + return -EINVAL; >> + >> + args->pitch = pitch; >> + >> + return drm_mode_align_dumb(args, pitch_align, size_align); >> +} >> +EXPORT_SYMBOL(drm_mode_size_dumb); >> + >> int drm_mode_create_dumb(struct drm_device *dev, >> struct drm_mode_create_dumb *args, >> struct drm_file *file_priv) >> diff --git a/include/drm/drm_dumb_buffers.h b/include/drm/drm_dumb_buffers.h >> new file mode 100644 >> index 000000000000..6fe36004b19d >> --- /dev/null >> +++ b/include/drm/drm_dumb_buffers.h >> @@ -0,0 +1,14 @@ >> +/* SPDX-License-Identifier: MIT */ >> + >> +#ifndef __DRM_DUMB_BUFFERS_H__ >> +#define __DRM_DUMB_BUFFERS_H__ >> + >> +struct drm_device; >> +struct drm_mode_create_dumb; >> + >> +int drm_mode_size_dumb(struct drm_device *dev, >> + struct drm_mode_create_dumb *args, >> + unsigned long pitch_align, >> + unsigned long size_align); >> + >> +#endif >> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h >> index c082810c08a8..eea09103b1a6 100644 >> --- a/include/uapi/drm/drm_mode.h >> +++ b/include/uapi/drm/drm_mode.h >> @@ -1058,7 +1058,7 @@ struct drm_mode_crtc_page_flip_target { >> * struct drm_mode_create_dumb - Create a KMS dumb buffer for scanout. >> * @height: buffer height in pixels >> * @width: buffer width in pixels >> - * @bpp: bits per pixel >> + * @bpp: color mode >> * @flags: must be zero >> * @handle: buffer object handle >> * @pitch: number of bytes between two consecutive lines >> @@ -1066,6 +1066,50 @@ struct drm_mode_crtc_page_flip_target { >> * >> * User-space fills @height, @width, @bpp and @flags. If the IOCTL succeeds, >> * the kernel fills @handle, @pitch and @size. >> + * >> + * The value of @bpp is a color-mode number describing a specific format >> + * or a variant thereof. The value often corresponds to the number of bits >> + * per pixel for most modes, although there are exceptions. Each color mode >> + * maps to a DRM format plus a number of modes with similar pixel layout. >> + * Framebuffer layout is always linear. >> + * >> + * Support for all modes and formats is optional. Even if dumb-buffer >> + * creation with a certain color mode succeeds, it is not guaranteed that >> + * the DRM driver supports any of the related formats. Most drivers support >> + * a color mode of 32 with a format of DRM_FORMAT_XRGB8888 on their primary >> + * plane. >> + * >> + * +------------+------------------------+------------------------+ >> + * | Color mode | Framebuffer format | Compatibles | >> + * +============+========================+========================+ >> + * | 32 | * DRM_FORMAT_XRGB8888 | * DRM_FORMAT_XBGR8888 | >> + * | | | * DRM_FORMAT_RGBX8888 | >> + * | | | * DRM_FORMAT_BGRX8888 | >> + * +------------+------------------------+------------------------+ >> + * | 24 | * DRM_FORMAT_RGB888 | * DRM_FORMAT_BGR888 | >> + * +------------+------------------------+------------------------+ >> + * | 16 | * DRM_FORMAT_RGB565 | * DRM_FORMAT_BGR565 | >> + * +------------+------------------------+------------------------+ >> + * | 15 | * DRM_FORMAT_XRGB1555 | * DRM_FORMAT_XBGR1555 | >> + * | | | * DRM_FORMAT_RGBX1555 | >> + * | | | * DRM_FORMAT_BGRX1555 | >> + * +------------+------------------------+------------------------+ >> + * | 8 | * DRM_FORMAT_C8 | * DRM_FORMAT_R8 | > + DRM_FORMAT_D8? (and 4/2/1 below) Right, missed that. > > And DRM_FORMAT_Y8, if/when Tomi's series introducing that is accepted... Sure, if it is compatible, it can also go into the third column. Best regards Thomas > >> + * +------------+------------------------+------------------------+ >> + * | 4 | * DRM_FORMAT_C4 | * DRM_FORMAT_R4 | >> + * +------------+------------------------+------------------------+ >> + * | 2 | * DRM_FORMAT_C2 | * DRM_FORMAT_R2 | >> + * +------------+------------------------+------------------------+ >> + * | 1 | * DRM_FORMAT_C1 | * DRM_FORMAT_R1 | >> + * +------------+------------------------+------------------------+ >> + * >> + * Color modes of 10, 12, 15, 30 and 64 are only supported for use by >> + * legacy user space. Please don't use them in new code. Other modes >> + * are not support. >> + * >> + * Do not attempt to allocate anything but linear framebuffer memory >> + * with single-plane RGB data. Allocation of other framebuffer >> + * layouts requires dedicated ioctls in the respective DRM driver. >> */ >> struct drm_mode_create_dumb { >> __u32 height; > Gr{oetje,eeting}s, > > Geert >
Hi Am 20.02.25 um 10:18 schrieb Tomi Valkeinen: [...] >> + * Color modes of 10, 12, 15, 30 and 64 are only supported for use by >> + * legacy user space. Please don't use them in new code. Other modes >> + * are not support. >> + * >> + * Do not attempt to allocate anything but linear framebuffer memory >> + * with single-plane RGB data. Allocation of other framebuffer >> + * layouts requires dedicated ioctls in the respective DRM driver. > > According to this, every driver that supports, say, NV12, should > implement their own custom ioctl to do the exact same thing? And, of > course, every userspace app that uses, say, NV12, should then add code > for all these platforms to call the custom ioctls? Yes, that's exactly the current status. There has been discussion about a new dumb-create ioctl that takes a DRM format as parameter. I'm all for it, but it's out of the scope for this series. > > As libdrm's modetest currently supports YUV formats with dumb buffers, > should we remove that code, as it's not correct and I'm sure people > use libdrm code as a reference? Of course not. > > Well, I'm not serious above, but I think all my points from the > earlier version are still valid. I don't like this. It changes the > parameters of the ioctl (bpp used to be bits-per-pixel, not it's > "color mode"), and the behavior of the ioctl, behavior that we've had > for a very long time, and we have no idea how many users there are > that will break (could be none, of course). And the documentation > changes make the current behavior and uses wrong or legacy. Before I go into details about this statement, what use case exactly are you referring to when you say that behavior changes? Best regards Thomas > > Clearly we need something new and better for the buffer allocation, > but for the time being, I'd be more comfortable just keep the current > behavior, at least for all the drivers I use or maintain: omapdrm, > tidss, renesas, xlnx, tilcdc. > > Tomi >
Reviewed-by: Lyude Paul <lyude@redhat.com> On Tue, 2025-02-18 at 15:23 +0100, Thomas Zimmermann wrote: > Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch and > buffer size. Align the pitch to a multiple of 256. > > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> > Cc: Karol Herbst <kherbst@redhat.com> > Cc: Lyude Paul <lyude@redhat.com> > Cc: Danilo Krummrich <dakr@kernel.org> > --- > drivers/gpu/drm/nouveau/nouveau_display.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c > index add006fc8d81..daa2528f9c9a 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_display.c > +++ b/drivers/gpu/drm/nouveau/nouveau_display.c > @@ -30,6 +30,7 @@ > #include <drm/drm_atomic_helper.h> > #include <drm/drm_client_event.h> > #include <drm/drm_crtc_helper.h> > +#include <drm/drm_dumb_buffers.h> > #include <drm/drm_fourcc.h> > #include <drm/drm_gem_framebuffer_helper.h> > #include <drm/drm_probe_helper.h> > @@ -808,9 +809,9 @@ nouveau_display_dumb_create(struct drm_file *file_priv, struct drm_device *dev, > uint32_t domain; > int ret; > > - args->pitch = roundup(args->width * (args->bpp / 8), 256); > - args->size = args->pitch * args->height; > - args->size = roundup(args->size, PAGE_SIZE); > + ret = drm_mode_size_dumb(dev, args, SZ_256, 0); > + if (ret) > + return ret; > > /* Use VRAM if there is any ; otherwise fallback to system memory */ > if (nouveau_drm(dev)->client.device.info.ram_size != 0)
Hi Am 20.02.25 um 11:53 schrieb Tomi Valkeinen: > Hi, > > On 20/02/2025 12:05, Thomas Zimmermann wrote: >> Hi >> >> Am 20.02.25 um 10:18 schrieb Tomi Valkeinen: >> [...] >>>> + * Color modes of 10, 12, 15, 30 and 64 are only supported for use by >>>> + * legacy user space. Please don't use them in new code. Other modes >>>> + * are not support. >>>> + * >>>> + * Do not attempt to allocate anything but linear framebuffer memory >>>> + * with single-plane RGB data. Allocation of other framebuffer >>>> + * layouts requires dedicated ioctls in the respective DRM driver. >>> >>> According to this, every driver that supports, say, NV12, should >>> implement their own custom ioctl to do the exact same thing? And, of >>> course, every userspace app that uses, say, NV12, should then add >>> code for all these platforms to call the custom ioctls? >> >> Yes, that's exactly the current status. >> >> There has been discussion about a new dumb-create ioctl that takes a >> DRM format as parameter. I'm all for it, but it's out of the scope >> for this series. >> >>> >>> As libdrm's modetest currently supports YUV formats with dumb >>> buffers, should we remove that code, as it's not correct and I'm >>> sure people use libdrm code as a reference? >> >> Of course not. >> >>> >>> Well, I'm not serious above, but I think all my points from the >>> earlier version are still valid. I don't like this. It changes the >>> parameters of the ioctl (bpp used to be bits-per-pixel, not it's >>> "color mode"), and the behavior of the ioctl, behavior that we've >>> had for a very long time, and we have no idea how many users there >>> are that will break (could be none, of course). And the >>> documentation changes make the current behavior and uses wrong or >>> legacy. >> >> Before I go into details about this statement, what use case exactly >> are you referring to when you say that behavior changes? > > For every dumb_buffer allocation with bpp that is not divisible by 8, > the result is different, i.e. instead of DIV_ROUND_UP(width * bpp, 8), > we now have width * DIV_ROUND_UP(bpp, 8). This, of course, depends on > the driver implementation. Some already do the latter. The current dumb-buffer code does a stride computation at [1], which is correct for all cases; although over-allocates sometimes. It's the one you describe as "width * DIV_ROUND_UP(bpp, 8)". It's in the ioctl entry point, so it's somewhat authoritative for all driver's implementations. It's also used by several drivers. The other variant, "DIV_ROUND_UP(width * bpp, 8)", is used by gem-dma, gem-shmem and others. It can give incorrect results and possibly OOBs. To give a simple example, let's allocate 15-bit XRGB1555. Bpp is 15. With a width of 1024, that would result in 1920 bytes per scanline. But because XRGB1555 has a filler bit, so the pixel is actually 16 bit and a scanline needs to be 2048 bytes. The new code fixes that. This is not just a hypothetical scenario: we do have drivers that support XRGB1555 and some of them also export a preferred_depth of 15 to userspace. [2] In the nearby comment, you'll see that this value is meant for dumb buffers. Rounding up the depth value in user space is possible for RGB, but not for YUV. Here different pixel planes have a different number of bits. Sometimes pixels are sharing bits. The value of bits-per-pixel becomes meaningless. That's why it's also deprecated in struct drm_format_info. The struct instead uses a more complicated per-plane calculation to compute the number of bits per plane. [3] The user-space code currently doing YUV on dumb buffers simply got lucky. [1] https://elixir.bootlin.com/linux/v6.13.3/source/drivers/gpu/drm/drm_dumb_buffers.c#L77 [2] https://elixir.bootlin.com/linux/v6.13.3/source/include/drm/drm_mode_config.h#L885 [3] https://elixir.bootlin.com/linux/v6.13.3/source/include/drm/drm_fourcc.h#L83 > > This change also first calls the drm_driver_color_mode_format(), which > could change the behavior even more, but afaics at the moment does not. Because currently each driver does its own thing, it can be hard to write user space that reliably allocates on all drivers. That's why it's important that parameters are not just raw numbers, but have well-defined semantics. The raw bpp is meaningless; it's also important to know which formats are associated with each value. Otherwise, you might get a dumb buffer with a bpp of 15, but it will be displayed incorrectly. This patch series finally implements this and clearly documents the assumptions behind the interfaces. The assumptions themselves have always existed. The color modes in drm_driver_color_mode_format() are set in stone and will not change incompatibly. It's already a user interface. I've taken care that the results do not change incompatibly compared to what the dumb-buffer ioctl currently assumes. (C1-C4 are special, see below.) > Although, maybe some platform does width * DIV_ROUND_UP(bpp, 8) even > for bpp < 8, and then this series changes it for 1, 2 and 4 bpps (but > not for 3, 5, 6, 7, if I'm not mistaken). True. 1, 2 and 4 would currently over-allocate significantly on some drivers and the series will reduce this to actual requirements. Yet our most common memory managers, gem-dma and gem-shmem, compute the sizes correctly. But there are currently no drivers that support C4, C2 or C1 formats; hence there's likely no user space either. I know that Geert is interested in making a driver that uses these formats on very low-end hardware (something Atari or Amiga IIRC). Over-allocating on such hardware is likely not an option. The other values (3, 5, 6, 7) have no meaning I know of. 6 could be XRGB2222, but I not aware of anything using that. We don't even have a format constant for this. > > However, as the bpp is getting rounded up, this probably won't break > any user. But it _is_ a change in the behavior of a uapi, and every > time we change a uapi that's been out there for a long time, I'm > getting slightly uncomfortable. As I tried to explain, we currently have both versions in drivers: rounding up bpp and rounding up (bpp*width). User-space code already has to deal with both cases. Best regards Thomas > > So, as a summary, I have a feeling that nothing will break, but I > can't say for sure. And as I'm having trouble seeing the benefit of > this change for the user, I get even more uncomfortable. > > Tomi >
Hi Thomas, On Fri, 21 Feb 2025 at 10:19, Thomas Zimmermann <tzimmermann@suse.de> wrote: > Am 20.02.25 um 11:53 schrieb Tomi Valkeinen: > > This change also first calls the drm_driver_color_mode_format(), which > > could change the behavior even more, but afaics at the moment does not. > > Because currently each driver does its own thing, it can be hard to > write user space that reliably allocates on all drivers. That's why it's > important that parameters are not just raw numbers, but have > well-defined semantics. The raw bpp is meaningless; it's also important > to know which formats are associated with each value. Otherwise, you > might get a dumb buffer with a bpp of 15, but it will be displayed > incorrectly. This patch series finally implements this and clearly > documents the assumptions behind the interfaces. The assumptions > themselves have always existed. > > The color modes in drm_driver_color_mode_format() are set in stone and > will not change incompatibly. It's already a user interface. I've taken > care that the results do not change incompatibly compared to what the > dumb-buffer ioctl currently assumes. (C1-C4 are special, see below.) > > > Although, maybe some platform does width * DIV_ROUND_UP(bpp, 8) even > > for bpp < 8, and then this series changes it for 1, 2 and 4 bpps (but > > not for 3, 5, 6, 7, if I'm not mistaken). > > True. 1, 2 and 4 would currently over-allocate significantly on some > drivers and the series will reduce this to actual requirements. Yet our > most common memory managers, gem-dma and gem-shmem, compute the sizes > correctly. > > But there are currently no drivers that support C4, C2 or C1 formats; > hence there's likely no user space either. I know that Geert is > interested in making a driver that uses these formats on very low-end > hardware (something Atari or Amiga IIRC). Over-allocating on such > hardware is likely not an option. Note that the gud and ssd130x drivers do support R1, and I believe work is underway to add grayscale formats to ssd130x. > The other values (3, 5, 6, 7) have no meaning I know of. 6 could be > XRGB2222, but I not aware of anything using that. We don't even have a > format constant for this. Yeah, e.g. Amiga supports 3, 5, 6, and 7 bpp, but that is using bitplanes. There is already some sort of consensus to not expose bitplanes to userspace in DRM, so limiting to 1, 2, 4, and 8 bpp (which can be converted from C[1248]) is fine. Gr{oetje,eeting}s, Geert
Hi Am 21.02.25 um 10:57 schrieb Geert Uytterhoeven: > Hi Thomas, > > On Fri, 21 Feb 2025 at 10:19, Thomas Zimmermann <tzimmermann@suse.de> wrote: >> Am 20.02.25 um 11:53 schrieb Tomi Valkeinen: >>> This change also first calls the drm_driver_color_mode_format(), which >>> could change the behavior even more, but afaics at the moment does not. >> Because currently each driver does its own thing, it can be hard to >> write user space that reliably allocates on all drivers. That's why it's >> important that parameters are not just raw numbers, but have >> well-defined semantics. The raw bpp is meaningless; it's also important >> to know which formats are associated with each value. Otherwise, you >> might get a dumb buffer with a bpp of 15, but it will be displayed >> incorrectly. This patch series finally implements this and clearly >> documents the assumptions behind the interfaces. The assumptions >> themselves have always existed. >> >> The color modes in drm_driver_color_mode_format() are set in stone and >> will not change incompatibly. It's already a user interface. I've taken >> care that the results do not change incompatibly compared to what the >> dumb-buffer ioctl currently assumes. (C1-C4 are special, see below.) >> >>> Although, maybe some platform does width * DIV_ROUND_UP(bpp, 8) even >>> for bpp < 8, and then this series changes it for 1, 2 and 4 bpps (but >>> not for 3, 5, 6, 7, if I'm not mistaken). >> True. 1, 2 and 4 would currently over-allocate significantly on some >> drivers and the series will reduce this to actual requirements. Yet our >> most common memory managers, gem-dma and gem-shmem, compute the sizes >> correctly. >> >> But there are currently no drivers that support C4, C2 or C1 formats; >> hence there's likely no user space either. I know that Geert is >> interested in making a driver that uses these formats on very low-end >> hardware (something Atari or Amiga IIRC). Over-allocating on such >> hardware is likely not an option. > Note that the gud and ssd130x drivers do support R1, and I believe > work is underway to add grayscale formats to ssd130x. Nice find. Both use gem-shmem, which allocates without much overhead. So any possible userspace should already be prepared for this scenario. > >> The other values (3, 5, 6, 7) have no meaning I know of. 6 could be >> XRGB2222, but I not aware of anything using that. We don't even have a >> format constant for this. > Yeah, e.g. Amiga supports 3, 5, 6, and 7 bpp, but that is using > bitplanes. There is already some sort of consensus to not expose > bitplanes to userspace in DRM, so limiting to 1, 2, 4, and 8 bpp > (which can be converted from C[1248]) is fine. There's been discussion about a new dumb-buffer ioctl that receives a format constant and returns individual buffers for each plane. This would allow for these use cases. Best regards Thomas > > Gr{oetje,eeting}s, > > Geert >
Dumb-buffer pitch and size is specified by width, height, bits-per-pixel plus various hardware-specific alignments. The calculation of these values is inconsistent and duplicated among drivers. The results for formats with bpp < 8 are incorrect. This series fixes this for most drivers. Default scanline pitch and buffer size are now calculated with the existing 4CC helpers. There is a new helper drm_mode_size_dumb() that calculates scanline pitch and buffer size according to driver requirements. The series fixes the common GEM implementations for DMA, SHMEM and VRAM. It further changes most implementations of dumb_create to use the new helper. A small number of drivers has more complicated calculations and will be updated by a later patches. v3: - document UAPI semantics - fall back to bpp-based allocation for unknown color modes - cleanups v2: - rewrite series - convert many individual drivers besides the shared GEM helpers Thomas Zimmermann (25): drm/dumb-buffers: Sanitize output on errors drm/dumb-buffers: Provide helper to set pitch and size drm/gem-dma: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/gem-shmem: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/gem-vram: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/armada: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/exynos: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/gma500: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/hibmc: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/imx/ipuv3: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/loongson: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/mediatek: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/msm: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/nouveau: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/omapdrm: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/qxl: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/renesas/rcar-du: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/renesas/rz-du: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/rockchip: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/tegra: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/virtio: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/vmwgfx: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/xe: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/xen: Compute dumb-buffer sizes with drm_mode_size_dumb() drm/xlnx: Compute dumb-buffer sizes with drm_mode_size_dumb() drivers/gpu/drm/armada/armada_gem.c | 16 +- drivers/gpu/drm/drm_dumb_buffers.c | 156 ++++++++++++++++-- drivers/gpu/drm/drm_gem_dma_helper.c | 7 +- drivers/gpu/drm/drm_gem_shmem_helper.c | 16 +- drivers/gpu/drm/drm_gem_vram_helper.c | 89 +++------- drivers/gpu/drm/exynos/exynos_drm_gem.c | 8 +- drivers/gpu/drm/gma500/gem.c | 21 +-- .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 25 ++- drivers/gpu/drm/imx/ipuv3/imx-drm-core.c | 29 +++- drivers/gpu/drm/loongson/lsdc_gem.c | 29 +--- drivers/gpu/drm/mediatek/mtk_gem.c | 13 +- drivers/gpu/drm/msm/msm_gem.c | 27 ++- drivers/gpu/drm/nouveau/nouveau_display.c | 7 +- drivers/gpu/drm/omapdrm/omap_gem.c | 15 +- drivers/gpu/drm/qxl/qxl_dumb.c | 17 +- drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c | 7 +- drivers/gpu/drm/renesas/rz-du/rzg2l_du_kms.c | 7 +- drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 12 +- drivers/gpu/drm/tegra/gem.c | 8 +- drivers/gpu/drm/virtio/virtgpu_gem.c | 11 +- drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 21 +-- drivers/gpu/drm/xe/xe_bo.c | 8 +- drivers/gpu/drm/xen/xen_drm_front.c | 7 +- drivers/gpu/drm/xlnx/zynqmp_kms.c | 7 +- include/drm/drm_dumb_buffers.h | 14 ++ include/drm/drm_gem_vram_helper.h | 6 - include/uapi/drm/drm_mode.h | 46 +++++- 27 files changed, 401 insertions(+), 228 deletions(-) create mode 100644 include/drm/drm_dumb_buffers.h