topic i.MX Framebuffer queries in i.MX Processors

i.MX Framebuffer queries

positron — Wed, 18 Apr 2012 12:45:25 GMT

I'm using a mx53 QSB along with a TFT touch panel.

When going thro the imxfb.h under arch/arm/plat-mxc/include/mach/imxfb.h

I notice this structure.

struct imx_fb_videomode {
   struct fb_videomode mode;
   u32 pcr;
   unsigned char   bpp;
};

What does this pcr and bpp symbolize? I'm totally new to framebuffers and any pointers on this would be appreciated.

Thanks

Re: i.MX Framebuffer queries

KursadOney — Wed, 18 Apr 2012 18:00:31 GMT

bpp is bits per pixel.

It looks like pcr comes from here: http://cache.freescale.com/files/32bit/doc/app_note/AN2868.pdf and is for "panel configuration register". This name does not appear in the mx53 manual though so it's either renamed or not exactly used for mx53. I'm not sure.

Re: i.MX Framebuffer queries

positron — Thu, 19 Apr 2012 01:51:33 GMT

Thanks Kursad. I'll have a look at the attachment. Also I wanted to know on what pcr takes. I see some cryptic hex values all around. There is no where, it is explained why. Any ideas to find out the one for my display?

(One can see the pcr values in latest kernel sources)

Re: i.MX Framebuffer queries

KursadOney — Thu, 19 Apr 2012 13:11:45 GMT

I think those values depend on your display. The user's manual for your display might have them listed. I'd start with some basic harmless values and modify if things look distorted or out of place. The link I put in my original reply goes over those a little bit too. Look for Panel Configuration Register. Older i.mx manual (maybe mx21?) might have more info.