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| author | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-11-09 14:52:20 +0100 |
|---|---|---|
| committer | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-11-13 08:52:24 +0100 |
| commit | 0049fb2603b7afb1080776ee691dfa5a3d282357 (patch) | |
| tree | 87a13be03223d34213fc9f213e0a480b365a4dd0 /Documentation/arm | |
| parent | OMAP: FB: use DMA_BIT_MASK() for fb's coherent_dma_mask (diff) | |
| download | linux-0049fb2603b7afb1080776ee691dfa5a3d282357.tar.xz linux-0049fb2603b7afb1080776ee691dfa5a3d282357.zip | |
OMAPFB: use dma_alloc_attrs to allocate memory
Use dma_alloc_attrs to allocate memory instead of omap specific vram
allocator. After this we can remove the omap vram allocator.
There are some downsides to this change:
1) dma_alloc_attrs doesn't let us allocate at certain physical address.
However, this should not be a problem as this feature of vram allocator
is only used when reserving the framebuffer that was initialized by the
bootloader, and we don't currently support "passing" a framebuffer from
the bootloader to the kernel anyway.
2) dma_alloc_attrs, as of now, always ioremaps the allocated area, and
we don't need the ioremap when using VRFB. This patch uses
DMA_ATTR_NO_KERNEL_MAPPING for the allocation, but the flag is currently
not operational.
3) OMAPFB_GET_VRAM_INFO ioctl cannot return real values anymore. I
changed the ioctl to return 64M for all the values, which, I hope, the
applications will interpret as "there's enough vram".
4) "vram" kernel parameter to define how much ram to reserve for video
use no longer works. The user needs to enable CMA and use "cma"
parameter.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Diffstat (limited to 'Documentation/arm')
| -rw-r--r-- | Documentation/arm/OMAP/DSS | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/Documentation/arm/OMAP/DSS b/Documentation/arm/OMAP/DSS index a564ceea9e98..4484e021290e 100644 --- a/Documentation/arm/OMAP/DSS +++ b/Documentation/arm/OMAP/DSS @@ -285,7 +285,10 @@ FB0 +-- GFX ---- LCD ---- LCD Misc notes ---------- -OMAP FB allocates the framebuffer memory using the OMAP VRAM allocator. +OMAP FB allocates the framebuffer memory using the standard dma allocator. You +can enable Contiguous Memory Allocator (CONFIG_CMA) to improve the dma +allocator, and if CMA is enabled, you use "cma=" kernel parameter to increase +the global memory area for CMA. Using DSI DPLL to generate pixel clock it is possible produce the pixel clock of 86.5MHz (max possible), and with that you get 1280x1024@57 output from DVI. @@ -301,11 +304,6 @@ framebuffer parameters. Kernel boot arguments --------------------- -vram=<size>[,<physaddr>] - - Amount of total VRAM to preallocate and optionally a physical start - memory address. For example, "10M". omapfb allocates memory for - framebuffers from VRAM. - omapfb.mode=<display>:<mode>[,...] - Default video mode for specified displays. For example, "dvi:800x400MR-24@60". See drivers/video/modedb.c. |