nanogui: question concerning accessing RAM
Subject:
question concerning accessing RAM
From:
"steven blakeslee" ####@####.####
Date:
24 Apr 2002 21:15:16 -0000
Message-Id: <F22iAkAagmQ5WTaYeVs000056bc@hotmail.com>
I'm working on a driver for embedded Linux 2.4 on a ppc board to use a 640
by 480 LCD. I've been able to set up the lcd registers and register the new
frame buffer. The problem is every time I try to use the frame buffer I get
an error.
Oops: kernel access of bad area, sig: 11
NIP: C0107D7C XER: 00000000 LR: C0107D30 SP: C3AD7E70 REGS: c3ad7dc0 TRAP:
0300
MSR: 00009032 EE: 1 PR: 0 FP: 0 ME: 1 IR/DR: 11
DAR: C0111380, DSISR: 82000000
TASK = c3ad6000[80] 'nano-X' Last syscall: 5
last math 00000000 last altivec 00000000
GPR00: C0111380 C3AD7E70 C3AD6000 00000000 00000000 00000000 C3BD9AEC
C3BD9010
GPR08: 0000001B C0111370 C3AD6000 38635619 24000022 10044D98 00000000
00000000
GPR16: 00000000 00000000 00000000 00000000 00009032 03AD7F40 00000000
C0002BC8
GPR24: C00028E0 00000000 C01E6750 C3BD9A90 00000000 C025DA14 00000000
C0262248
Call backtrace:
C0107D30 C00A5088 C00573AC C00572B0 C0057800 C0002984 7C0802A6
I use alloc_bootmem_pages(PAGE_SIZE*75) to allocate the memory, I do this in
m8xx_setup.c. I get a pointer and use a for loop to modify the memory I
just allocated, when the kernel initializes the lcd registers the
appropriate color shows on the LCD. The problem is after the kernel boots I
am unable to modify this ram again. I have tried using the frame buffer and
also I have tried several modules. If anyone can give advice I would
appreciate it.
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