summaryrefslogtreecommitdiffstats
path: root/Documentation/fb/pxafb.txt
AgeCommit message (Collapse)Author
2008-12-29[ARM] pxafb: add support for overlay1 and overlay2 as framebuffer devicesEric Miao
PXA27x and later processors support overlay1 and overlay2 on-top of the base framebuffer (although under-neath the base is also possible). They support palette and no-palette RGB formats, as well as YUV formats (only available on overlay2). These overlays have dedicated DMA channels and behave in a similar way as a framebuffer. This heavily simplified and re-structured work is based on the original pxafb_overlay.c (which is pending for mainline merge for a long time). The major problems with this pxafb_overlay.c are (if you are interested in the history): 1. heavily redundant (the control logics for overlay1 and overlay2 are actually identical except for some small operations, which are now abstracted into a 'pxafb_layer_ops' structure) 2. a lot of useless and un-tested code (two workarounds which are now fixed on mature silicons) 3. cursorfb is actually useless, hardware cursor should not be used this way, and the code was actually un-tested for a long time. The code in this patch should be self-explanatory, I tried to add minimum comments. As said, this is basically simplified, there are several things still on the pending list: 1. palette mode is un-supported and un-tested (although re-using the palette code of the base framebuffer is actually very easy now with previous clean-up patches) 2. fb_pan_display for overlay(s) is un-supported 3. the base framebuffer can actually be abstracted by 'pxafb_layer' as well, which will help further re-use of the code and keep a better and consistent structure. (This is the reason I named it 'pxafb_layer' instead of 'pxafb_overlay' or something alike) See Documentation/fb/pxafb.txt for additional usage information. Signed-off-by: Eric Miao <eric.miao@marvell.com> Cc: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Eric Miao <ycmiao@ycmiao-hp520.(none)>
2008-12-29[ARM] pxafb: allow video memory size to be configurableEric Miao
The amount of video memory size is decided according to the following order: 1. <xres> x <yres> x <bits_per_pixel> by default, which is the backward compatible way 2. size specified in platform data 3. size specified in module parameter 'options' string or specified in kernel boot command line (see updated Documentation/fb/pxafb.txt) And now since the memory is allocated from system memory, the pxafb_mmap can be removed and the default fb_mmap() should be working all right. Also, since we now have introduced the 'struct pxafb_dma_buff' for DMA descriptors and palettes, the allocation can be separated cleanly. NOTE: the LCD DMA actually supports chained transfer (i.e. page-based transfers), to simplify the logic and keep the performance (with less TLB misses when accessing from memory mapped user space), the memory is allocated by alloc_pages_*() to ensures it's physical contiguous. Signed-off-by: Eric Miao <eric.miao@marvell.com> Signed-off-by: Eric Miao <ycmiao@ycmiao-hp520.(none)>
2005-04-16Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!