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remarkable-linux/drivers/staging/omapdrm/TODO

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staging: add omapdrm DRM/KMS driver for TI OMAP platforms A DRM display driver for TI OMAP platform. Similar to omapfb (fbdev) and omap_vout (v4l2 display) drivers in the past, this driver uses the DSS2 driver to access the display hardware, including support for HDMI, DVI, and various types of LCD panels. And it implements GEM support for buffer allocation (for KMS as well as offscreen buffers used by the xf86-video-omap userspace xorg driver). The driver maps CRTCs to overlays, encoders to overlay-managers, and connectors to dssdev's. Note that this arrangement might change slightly when support for drm_plane overlays is added. For GEM support, non-scanout buffers are using the shmem backed pages provided by GEM core (In drm_gem_object_init()). In the case of scanout buffers, which need to be physically contiguous, those are allocated with CMA and use drm_gem_private_object_init(). See userspace xorg driver: git://github.com/robclark/xf86-video-omap.git Refer to this link for CMA (Continuous Memory Allocator): http://lkml.org/lkml/2011/8/19/302 Links to previous versions of the patch: v1: http://lwn.net/Articles/458137/ v2: http://patches.linaro.org/4156/ v3: http://patches.linaro.org/4688/ v4: http://patches.linaro.org/4791/ History: v5: move headers from include/drm at Greg KH's request, minor rebasing on 3.2-rc1, pull in private copies of drm_gem_{get,put}_pages() because "drm/gem: add functions to get/put pages" patch is not merged yet v4: bit of rework of encoder/connector _dpms() code, modeset_init() rework to not use nested functions, update TODO.txt v3: minor cleanups, improved error handling for dev_load(), some minor API changes that will be needed later for tiled buffer support v2: replace omap_vram with CMA for scanout buffer allocation, remove unneeded functions, use dma_addr_t for physical addresses, error handling cleanup, refactor attach/detach pages into common drm functions, split non-userspace-facing API into omap_priv.h, remove plugin API v1: original Signed-off-by: Rob Clark <rob@ti.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-12 11:09:40 -07:00
TODO
. add video decode/encode support (via syslink3 + codec-engine)
staging: drm/omap: update TODO Update TODO file, which had been neglected. Signed-off-by: Rob Clark <rob@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-27 14:11:38 -06:00
. NOTE: with dmabuf this probably could be split into different driver
so perhaps this TODO doesn't belong here
staging: add omapdrm DRM/KMS driver for TI OMAP platforms A DRM display driver for TI OMAP platform. Similar to omapfb (fbdev) and omap_vout (v4l2 display) drivers in the past, this driver uses the DSS2 driver to access the display hardware, including support for HDMI, DVI, and various types of LCD panels. And it implements GEM support for buffer allocation (for KMS as well as offscreen buffers used by the xf86-video-omap userspace xorg driver). The driver maps CRTCs to overlays, encoders to overlay-managers, and connectors to dssdev's. Note that this arrangement might change slightly when support for drm_plane overlays is added. For GEM support, non-scanout buffers are using the shmem backed pages provided by GEM core (In drm_gem_object_init()). In the case of scanout buffers, which need to be physically contiguous, those are allocated with CMA and use drm_gem_private_object_init(). See userspace xorg driver: git://github.com/robclark/xf86-video-omap.git Refer to this link for CMA (Continuous Memory Allocator): http://lkml.org/lkml/2011/8/19/302 Links to previous versions of the patch: v1: http://lwn.net/Articles/458137/ v2: http://patches.linaro.org/4156/ v3: http://patches.linaro.org/4688/ v4: http://patches.linaro.org/4791/ History: v5: move headers from include/drm at Greg KH's request, minor rebasing on 3.2-rc1, pull in private copies of drm_gem_{get,put}_pages() because "drm/gem: add functions to get/put pages" patch is not merged yet v4: bit of rework of encoder/connector _dpms() code, modeset_init() rework to not use nested functions, update TODO.txt v3: minor cleanups, improved error handling for dev_load(), some minor API changes that will be needed later for tiled buffer support v2: replace omap_vram with CMA for scanout buffer allocation, remove unneeded functions, use dma_addr_t for physical addresses, error handling cleanup, refactor attach/detach pages into common drm functions, split non-userspace-facing API into omap_priv.h, remove plugin API v1: original Signed-off-by: Rob Clark <rob@ti.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-12 11:09:40 -07:00
. where should we do eviction (detatch_pages())? We aren't necessarily
accessing the pages via a GART, so maybe we need some other threshold
to put a cap on the # of pages that can be pin'd. (It is mostly only
of interest in case you have a swap partition/file.. which a lot of
these devices do not.. but it doesn't hurt for the driver to do the
right thing anyways.)
. Use mm_shrinker to trigger unpinning pages. Need to figure out how
to handle next issue first (I think?)
. Note TTM already has some mm_shrinker stuff.. maybe an argument to
move to TTM? Or maybe something that could be factored out in common?
. GEM/shmem backed pages can have existing mappings (kernel linear map,
etc..), which isn't really ideal.
. Revisit GEM sync object infrastructure.. TTM has some framework for this
already. Possibly this could be refactored out and made more common?
There should be some way to do this with less wheel-reinvention.
. Review DSS vs KMS mismatches. The omap_dss_device is sort of part encoder,
part connector. Which results in a bit of duct tape to fwd calls from
encoder to connector. Possibly this could be done a bit better.
drm/omap: add GEM support for tiled/dmm buffers TILER/DMM provides two features for omapdrm GEM objects: 1) providing a physically contiguous view to discontiguous memory for hw initiators that cannot otherwise support discontiguous buffers (DSS scanout, IVAHD video decode/encode, etc) 2) providing untiling for 2d tiled buffers, which are used in some cases to provide rotation and reduce memory bandwidth for hw initiators that tend to access data in 2d block patterns. For 2d tiled buffers, there are some additional complications when it comes to userspace mmap'ings. For non-tiled buffers, the original (potentially physically discontiguous) pages are used to back the mmap. For tiled buffers, we need to mmap via the tiler/dmm region to provide an unswizzled view of the buffer. But (a) the buffer is not necessarily pinned in TILER all the time (it can be unmapped when there is no DMA access to the buffer), and (b) when they are they are pinned, they not necessarily page aligned from the perspective of the CPU. And non-page aligned userspace buffer mapping is evil. To solve this, we reserve one or more small regions in each of the 2d containers when the driver is loaded to use as a "user-GART" where we can create a second page-aligned mapping of parts of the buffer being accessed from userspace. Page faulting is used to evict and remap different regions of whichever buffers are being accessed from user- space. Signed-off-by: Rob Clark <rob@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-05 18:19:22 -07:00
. Solve PM sequencing on resume. DMM/TILER must be reloaded before any
access is made from any component in the system. Which means on suspend
CRTC's should be disabled, and on resume the LUT should be reprogrammed
before CRTC's are re-enabled, to prevent DSS from trying to DMA from a
buffer mapped in DMM/TILER before LUT is reloaded.
staging: add omapdrm DRM/KMS driver for TI OMAP platforms A DRM display driver for TI OMAP platform. Similar to omapfb (fbdev) and omap_vout (v4l2 display) drivers in the past, this driver uses the DSS2 driver to access the display hardware, including support for HDMI, DVI, and various types of LCD panels. And it implements GEM support for buffer allocation (for KMS as well as offscreen buffers used by the xf86-video-omap userspace xorg driver). The driver maps CRTCs to overlays, encoders to overlay-managers, and connectors to dssdev's. Note that this arrangement might change slightly when support for drm_plane overlays is added. For GEM support, non-scanout buffers are using the shmem backed pages provided by GEM core (In drm_gem_object_init()). In the case of scanout buffers, which need to be physically contiguous, those are allocated with CMA and use drm_gem_private_object_init(). See userspace xorg driver: git://github.com/robclark/xf86-video-omap.git Refer to this link for CMA (Continuous Memory Allocator): http://lkml.org/lkml/2011/8/19/302 Links to previous versions of the patch: v1: http://lwn.net/Articles/458137/ v2: http://patches.linaro.org/4156/ v3: http://patches.linaro.org/4688/ v4: http://patches.linaro.org/4791/ History: v5: move headers from include/drm at Greg KH's request, minor rebasing on 3.2-rc1, pull in private copies of drm_gem_{get,put}_pages() because "drm/gem: add functions to get/put pages" patch is not merged yet v4: bit of rework of encoder/connector _dpms() code, modeset_init() rework to not use nested functions, update TODO.txt v3: minor cleanups, improved error handling for dev_load(), some minor API changes that will be needed later for tiled buffer support v2: replace omap_vram with CMA for scanout buffer allocation, remove unneeded functions, use dma_addr_t for physical addresses, error handling cleanup, refactor attach/detach pages into common drm functions, split non-userspace-facing API into omap_priv.h, remove plugin API v1: original Signed-off-by: Rob Clark <rob@ti.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-12 11:09:40 -07:00
Userspace:
. git://github.com/robclark/xf86-video-omap.git
Currently tested on
. OMAP3530 beagleboard
. OMAP4430 pandaboard
. OMAP4460 pandaboard
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