Re: [PATCH] CorebootPayloadPkg: Use correct BytesPerScanLine

["You, Benjamin" <benjamin.you@intel.com>]

Hi Nico,

Thanks for the documentation that is very clear.

Thanks,

- ben

> -----Original Message-----
> From: Nico Huber [mailto:nico.h@gmx.de]
> Sent: Sunday, January 28, 2018 10:34 PM
> To: You, Benjamin <benjamin.you@intel.com>; edk2-devel@lists.01.org
> Cc: Arthur Heymans <arthur@aheymans.xyz>
> Subject: Re: [edk2] [PATCH] CorebootPayloadPkg: Use correct BytesPerScanLine
> 
> Hi Ben,
> 
> On 28.01.2018 09:49, You, Benjamin wrote:
> > Hi Nico,
> >
> > Thanks for the detailed information. It makes sense. I do like the idea of
> > documenting the lb_framebuffer.
> >
> >> The only guarantee for `bytes_per_pixel` (typo? 'bytes_per_scanline')
> 
> yes, typo.
> 
> >> and `x_resolution` you get as a consumer, is that the former is big
> >> enough to hold `x_resolution` pixels.
> >
> > I think it would be good to also document that the consumer is assured that
> > in framebuffer, all the 'x_resolution' pixels are aligned at the beginning
> > of each scanline, and the extra bytes are always padded after the
> > 'x_resolution' pixels in the scanline. Would this be true with existing
> > graphics devices? (I am not expert in this area so I'd like to confirm.)
> 
> Yes, that's true. I've started to document the whole thing now:
> 
> https://review.coreboot.org/#/c/coreboot/+/23466/4/src/commonlib/include/
> commonlib/coreboot_tables.h@214
> 
> The same applies in principle to EFI_GRAPHICS_OUTPUT_MODE_INFORMATION.
> This framebuffer layout is very common.
> 
> Nico