What Might Cause This To Fail?

[el_pango]

Hi,

In my code, I'm trying to do this:

	system("ofbset -fb /dev/fb1 -pos 0 0 -size 800 480 -mem 192000 -en 1 ");
	system("fbset -fb /dev/fb1 -g 400 240 400 240 16");
	
	fbdev 	= open("/dev/fb1", O_RDONLY);
	
	if(fbdev == -1) exit(2);
	
	scrn_ptr = mmap(0,400 * 240 * 2, PROT_WRITE | PROT_READ, MAP_SHARED, fbdev, 0);

Unfortunately, mmap()ing doesn't work and leaves scrn_ptr as MAP_FAILED. What am I doing wrong here? Is this no longer supported?

Learned/stole ideas from http://pandorawiki.org/Kernel_interfacek

 

[urjaman]

	fbdev 	= open("/dev/fb1", O_RDONLY);

FWIW I'd try O_RDWR here unless its specified otherwise somewhere.

 

[skeezix]

Perhaps specify the path.

jeff

 

[notaz]

	fbdev 	= open("/dev/fb1", O_RDONLY);

FWIW I'd try O_RDWR here unless its specified otherwise somewhere.

Yeah you've opening the framebuffer as readonly (O_RDONLY), but want to have it's memory writeable (PROT_WRITE).