[U-Boot-Users] Re: How can I reserve memory for LCD framebuffer on ARM-based board?

Ilya Yanok ilya.yanok at gmail.com
Sat May 6 16:06:37 CEST 2006

Wolfgang Denk <wd <at> denx.de> writes:   
> Why do you think that reserving memory above the  BSS  segmet  was  a   
> problem?   
> And "don't even tries to ensure that there are enough memory" - well,   
> it is obviously the responsibility of the person porting U-Boot to  a   
> specific board to come up with a valid memory map.   
To be more precise I just try to ask where exactly I should make changes to   
reserve memory for framebuffer?   
> Oops? I don't understand. The existing code works fine on a couple of   
> boards. What's your specific problem? What exactly  makes  you  think   
> you cannot to the same?   
Existing code works fine, but writers of lib_arm/board.c and common/lcd.c for  
sure were thinking about different things...   
Code from lib_arm/board.c:  
size = lcd_setmem (addr);  
gd->fb_base = addr;  
But lcd_setmem(addr) returns not size of framebuffer but addr - size and  
reports of reserving framebuffer at addr - size. This don't make things broken  
but obviously is some kind of misunderstanding...  
This makes me think that somewhere (obviously not on ARM boards) we reserve  
framebuffer below u-boot code, so second question is why not to do this  
With best regards,  

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