[RPI BSP] fbcons implementation and EDID lecture

QIAO YANG yangqiao0505 at me.com
Mon Jun 8 09:53:21 UTC 2015


I've got a few questions over the fbcons implementation details and edid lecture:

1.  I should place the video init function where exactly? In the end of bspstarthooks.c  hook_1() or in the bspstart.c ?

2.  I need to ensure the structure buffer is 16-byte aligned .  I use __attribute__((aligned (16))) to specific the alignement. Is there any rtems macro for this or it's ok that I use the compiler attribute for all structure definition?

3. Is it necessary to encapsule the communication with videocore interfaces with individual functions? Or just let the developper construct the buffer to send in a certain structure with the macros defined? 

4. I've read many others' implementations of framebuffer. I've found that they all just query the display size by the videocore interface and use that for the resolution setup. So I wonder if it's obliged to get the EDID blocks, parse it then decide the resolution.  I proposed that we try to get the resolution from cmdline setup, use it if it's supported. If the setup is not supported, we'll query the display size. Normally the query can't fail as all others will throw an error when the query failed and stop the fbinit in their code (except for qemu emulator,  width=0,height= 0 will be returned) . If the query does fail, we will then try the default resolution: 640*480. 

For now, I think I've just need some more time to cleanup, write test samples and then send patches. If everything's ok next week I'll move to test and adapt the graphic libraries.

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