[igt-dev] [PATCH v8 13/16] chamelium: Change our pattern for a custom one if needed

[Arkadiusz Hiler]

On Thu, Oct 04, 2018 at 02:39:06PM +0200, Maxime Ripard wrote:
> The current pattern being used is the one generated through the
> igt_create_color_pattern_fb.
> 
> However, in order to deal with multiple formats and the upsampling /
> downsampling issues that might arise from converting back and forth between
> formats, we will need to have a pattern with quite precise color values,
> and without any shades or gradient of colors.
> 
> Let's create a function that will generate that pattern in the chamelium
> code if we need to convert the framebuffer to a smaller depth, and use the
> current pattern otherwise.
> 
> The easiest way to do that will be to only use values that would have the
> same part on the common most significant bits (5, to deal with most
> formats) and have the same bit repeated on the least significant bits that
> are going to be dropped and / or padded when converting between formats.
> 
> Pixman will fill the lowest bits with 1, and our hardware (this has been
> tested on a Raspberry Pi's VC4) is able to support that, so the easiest is
> to just use all 1's for our components in order to still be able to compute
> the CRCs.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard at bootlin.com>
Reviewed-by: Arkadiusz Hiler <arkadiusz.hiler at intel.com>