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| author | Rob Clark | 2011-12-06 02:19:22 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2011-12-09 00:04:21 +0100 |
| commit | f7f9f4536a09f9f73c800663df2e600c9405e1ef (patch) | |
| tree | 690d369e969039a54fec3a813d60b7acf5ea8207 /drivers/staging/omapdrm/TODO | |
| parent | drm/omap: DMM/TILER support for OMAP4+ platform (diff) | |
| download | kernel-qcow2-linux-f7f9f4536a09f9f73c800663df2e600c9405e1ef.tar.gz kernel-qcow2-linux-f7f9f4536a09f9f73c800663df2e600c9405e1ef.tar.xz kernel-qcow2-linux-f7f9f4536a09f9f73c800663df2e600c9405e1ef.zip | |
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>
Diffstat (limited to 'drivers/staging/omapdrm/TODO')
| -rw-r--r-- | drivers/staging/omapdrm/TODO | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/staging/omapdrm/TODO b/drivers/staging/omapdrm/TODO index 18677e777368..55b18377ac4f 100644 --- a/drivers/staging/omapdrm/TODO +++ b/drivers/staging/omapdrm/TODO @@ -22,6 +22,11 @@ TODO . 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. +. 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. . Add debugfs information for DMM/TILER Userspace: |