[PATCH v2 00/43] drm: Provide fbdev emulation per memory manager

Thomas Zimmermann
2024-04-10T13:06:02Z

DRM provides 3 different memory managers with slightly different
characteristics: DMA-based, SHMEM-based and TTM. This affects fbdev
emulation as each requires different handling of mmap(). This series
reworks fbdev emulation to provide an optimized emulation for each
of the memory managers.

Patch 1 fixes a minor bug in fbdev-generic.

Patches 2 to 8 implement fbdev-shmem, which is optimized for drivers
with SHMEM-based allocation. Patches 2 to 7 prepare deferred I/O to
support driver-custom page lookups. When the mmap'ed framebuffer sees
a pagefault, the deferred-I/O code can ask the graphics driver of the
page (instead of trying to detect it by itself). Using this hook,
patch 8 implements fbdev-shmem. The code is similar to fbdev-generic,
but does not require an additional shadow buffer for mmap(). Mmap'ed
pages are instead provided from the GEM buffer object. That saves a
few MiB of framebuffer memory and copying between the internal buffers.

Patches 9 to 20 convert SHMEM-based drivers to fbdev-shmem.

Patch 21 adds damage handling and deferred I/O to fbdev-dma. Such
code has been tested on the DMA-based omapdrm and can be adopted for
all drivers.

Patches 22 to 41 convert DMA-based drivers to fbdev-dma. These drivers
could not use it because of the missing support for damage handling.

Patch 42 renames fbdev-generic to fbdev-ttm. Only TTM-based drivers
still use it, so building it can be linked to TTM as well.

Patch 43 cleans up the documentation.

Tested with simpledrm, vc4 and amdgpu.

v2:
- fb-shmem: use drm_driver_legacy_fb_format()
- fix a few typos

Thomas Zimmermann (43):
drm/fbdev-generic: Do not set physical framebuffer address
fbdev/deferred-io: Move pageref setup into separate helper
fbdev/deferred-io: Clean up pageref on lastclose
fbdev/deferred-io: Test screen_buffer for vmalloc'ed memory
fbdev/deferred-io: Test smem_start for I/O memory
fbdev/deferred-io: Always call get_page() for framebuffer pages
fbdev/deferred-io: Provide get_page hook in struct fb_deferred_io
drm/fbdev: Add fbdev-shmem
drm/ast: Use fbdev-shmem
drm/gud: Use fbdev-shmem
drm/hyperv: Use fbdev-shmem
drm/mgag200: Use fbdev-shmem
drm/solomon: Use fbdev-shmem
drm/tiny/cirrus: Use fbdev-shmem
drm/tiny/gm12u320: Use fbdev-shmem
drm/tiny/ofdrm: Use fbdev-shmem
drm/tiny/simpledrm: Use fbdev-shmem
drm/udl: Use fbdev-shmem
drm/virtio: Use fbdev-shmem
drm/vkms: Use fbdev-shmem
drm/fbdev-dma: Implement damage handling and deferred I/O
drm/arm/komeda: Use fbdev-dma
drm/hisilicon/kirin: Use fbdev-dma
drm/imx/lcdc: Use fbdev-dma
drm/ingenic: Use fbdev-dma
drm/mediatek: Use fbdev-dma
drm/panel/panel-ilitek-9341: Use fbdev-dma
drm/renesas/rcar-du: Use fbdev-dma
drm/renesas/rz-du: Use fbdev-dma
drm/renesas/shmobile: Use fbdev-dma
drm/rockchip: Use fbdev-dma
drm/tiny/hx8357d: Use fbdev-dma
drm/tiny/ili9163: Use fbdev-dma
drm/tiny/ili9225: Use fbdev-dma
drm/tiny/ili9341: Use fbdev-dma
drm/tiny/ili9486: Use fbdev-dma
drm/tiny/mi0283qt: Use fbdev-dma
drm/tiny/panel-mipi-dbi: Use fbdev-dma
drm/tiny/repaper: Use fbdev-dma
drm/tiny/st7586: Use fbdev-dma
drm/tiny/st7735r: Use fbdev-dma
drm/fbdev-generic: Convert to fbdev-ttm
drm/fbdev: Clean up fbdev documentation

Documentation/gpu/drm-kms-helpers.rst | 12 +-
Documentation/gpu/todo.rst | 13 -
drivers/gpu/drm/Makefile | 6 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 6 +-
.../gpu/drm/arm/display/komeda/komeda_drv.c | 4 +-
drivers/gpu/drm/ast/ast_drv.c | 4 +-
drivers/gpu/drm/drm_drv.c | 2 +-
drivers/gpu/drm/drm_fb_helper.c | 11 +-
drivers/gpu/drm/drm_fbdev_dma.c | 65 +++-
drivers/gpu/drm/drm_fbdev_shmem.c | 316 ++++++++++++++++++
.../{drm_fbdev_generic.c => drm_fbdev_ttm.c} | 81 +++--
drivers/gpu/drm/gud/gud_drv.c | 4 +-
.../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 4 +-
.../gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 4 +-
drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 4 +-
drivers/gpu/drm/imx/lcdc/imx-lcdc.c | 4 +-
drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 4 +-
drivers/gpu/drm/loongson/Kconfig | 1 +
drivers/gpu/drm/loongson/lsdc_drv.c | 4 +-
drivers/gpu/drm/mediatek/mtk_drm_drv.c | 4 +-
drivers/gpu/drm/mgag200/mgag200_drv.c | 4 +-
drivers/gpu/drm/nouveau/nouveau_drm.c | 6 +-
drivers/gpu/drm/panel/panel-ilitek-ili9341.c | 4 +-
drivers/gpu/drm/qxl/qxl_drv.c | 4 +-
drivers/gpu/drm/renesas/rcar-du/rcar_du_drv.c | 4 +-
drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.c | 4 +-
.../gpu/drm/renesas/shmobile/shmob_drm_drv.c | 4 +-
drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 4 +-
drivers/gpu/drm/solomon/ssd130x.c | 4 +-
drivers/gpu/drm/tiny/bochs.c | 4 +-
drivers/gpu/drm/tiny/cirrus.c | 4 +-
drivers/gpu/drm/tiny/gm12u320.c | 4 +-
drivers/gpu/drm/tiny/hx8357d.c | 4 +-
drivers/gpu/drm/tiny/ili9163.c | 4 +-
drivers/gpu/drm/tiny/ili9225.c | 4 +-
drivers/gpu/drm/tiny/ili9341.c | 4 +-
drivers/gpu/drm/tiny/ili9486.c | 4 +-
drivers/gpu/drm/tiny/mi0283qt.c | 4 +-
drivers/gpu/drm/tiny/ofdrm.c | 4 +-
drivers/gpu/drm/tiny/panel-mipi-dbi.c | 4 +-
drivers/gpu/drm/tiny/repaper.c | 4 +-
drivers/gpu/drm/tiny/simpledrm.c | 4 +-
drivers/gpu/drm/tiny/st7586.c | 4 +-
drivers/gpu/drm/tiny/st7735r.c | 4 +-
drivers/gpu/drm/udl/udl_drv.c | 4 +-
drivers/gpu/drm/vboxvideo/vbox_drv.c | 4 +-
drivers/gpu/drm/virtio/virtgpu_drv.c | 4 +-
drivers/gpu/drm/vkms/vkms_drv.c | 4 +-
drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 4 +-
drivers/video/fbdev/core/fb_defio.c | 82 +++--
include/drm/drm_fbdev_generic.h | 15 -
include/drm/drm_fbdev_shmem.h | 15 +
include/drm/drm_fbdev_ttm.h | 15 +
include/drm/drm_mode_config.h | 4 +-
include/linux/fb.h | 1 +
55 files changed, 593 insertions(+), 210 deletions(-)
create mode 100644 drivers/gpu/drm/drm_fbdev_shmem.c
rename drivers/gpu/drm/{drm_fbdev_generic.c => drm_fbdev_ttm.c} (76%)
delete mode 100644 include/drm/drm_fbdev_generic.h
create mode 100644 include/drm/drm_fbdev_shmem.h
create mode 100644 include/drm/drm_fbdev_ttm.h

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2.44.0