da8xx-fb: Rounding FB size to satisfy SGX buffer requirements
authorAditya Nellutla <aditya.n@ti.com>
Wed, 23 May 2012 06:06:31 +0000 (11:36 +0530)
committerFlorian Tobias Schandinat <FlorianSchandinat@gmx.de>
Wed, 27 Jun 2012 07:01:38 +0000 (07:01 +0000)
commit3b9cc4ea4735d3c73ee27ef7b829b6fe4535eefe
tree0f7dcb034408d66ebe67a16bcfdb7eaed8d562d0
parent41a490ec019fd172f5d0356e01d8101b4708aee2
da8xx-fb: Rounding FB size to satisfy SGX buffer requirements

In the real time use-case when SGX is used for rendering to FB buffers it has been
observed that, the available memory from framebuffer driver is not sufficient for
SGX under certain cases (like 16-bit WVGA resolution). SGX requires 2 swap buffers
with each of the buffers aligned to lcm(line_length, PAGE_SIZE).

Inorder to satisfy this requirement, we have two options,

- Increase number of FB buffers (LCD_NUM_BUFFERS) to 3. This is not
  recommended as we end up wasting huge memory in most of the cases.

- Align FB buffers to lcm(line_length, PAGE_SIZE).This ensures framebuffer
  size is increased to satisfy SGX requirements keeping alignment intact.

This patch makes sure that FB allocates buffers aligned to above formula.

Signed-off-by: Aditya Nellutla <aditya.n@ti.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
drivers/video/da8xx-fb.c