[Cbe-oss-dev] Hard crash on fb write past 17MB

Mike Acton macton at cellperformance.com
Tue Dec 19 22:08:15 EST 2006

Having a problem which causes a hard crash of the OS:

I can mmap 18MB from /dev/fb0 (whatever configuration: 1MB x 18, 18MB
x 1, etc.) without errors. (Trying to map more than 18MB is rejected
by mmap)

Writing in the range 0-17MB causes no problems.
Writing to the range 17-18MB causes the system to stop without any
apparent feedback.
Reading the range 0-18MB cases no problems.

I have a small test program which demonstrates the problem:

To compile: gcc -std=c99 test_fb_alloc.c -o test_fb_alloc

[It will prompt before the offending bit to give you a chance to skip it.]

This is on YDL5 for PS3 with kernel 2.6.16

Anyone have an idea?


PS: Did anyone notice that in Sony's vsync sample, mmap is being
checked for NULL instead of MAP_FAILED? mmap does seem to properly
return MAP_FAILED, so I expect this is just a typo in the sample.

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