-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Ian Romanick wrote:
> I'm in the process of modifying X to be civilized in it's handling of
> PCI devices on Linux. As part of that, I've modified it to map the
> /sys/bus/pci/device/*/resource[0-6] files instead of mucking about with
> /dev/mem.
>
> This seems to mostly work, but I am having one problem. I map the
> region by opening the file with O_RDWR, then mmap with
> (PROT_READ|PROT_WRITE) and MAP_SHARED. In all cases, the open and mmap
> succeed. However, for I/O BARs, the resulting pointer from mmap is
> invalid. Any access to it results in a segfault and GDB says it's "out
> of range".
I was a little mistaken about this. The BAR that causes the problem is
not I/O. It *is* memory.
01:00.0 VGA compatible controller: Matrox Graphics, Inc. G400/G450 (rev
03) (prog-if 00 [VGA])
Subsystem: Matrox Graphics, Inc. Millennium G400 16Mb SGRAM
Flags: bus master, medium devsel, latency 64, IRQ 11
Memory at cc000000 (32-bit, prefetchable) [size=32M]
Memory at cfefc000 (32-bit, non-prefetchable) [size=16K]
Memory at cf000000 (32-bit, non-prefetchable) [size=8M]
Expansion ROM at cfee0000 [disabled] [size=64K]
When I open and mmap resource0 (the framebuffer) I get 0x2b9aa48ea000.
When I open and mmap resource1 (the card's registers) I get
0x2b9aa68ea000. I can access the resource0 pointer all day long without
problems. The firs access to the resource1 pointer results in a segfault.
> The base address of the BAR is page aligned, so its not a problem with
> the alignment of mmap vs. the alignment of the BAR. What else could it
> be? I'm pretty stumped.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.2.1 (GNU/Linux)
iD8DBQFEPELpX1gOwKyEAw8RAjT+AJ0ZzDb49tr5WwKWE7eyKWdT7hRLUQCgkOSS
twDrsx8VrWG5xEf+hbbkFvg=
=im+D
-----END PGP SIGNATURE-----
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
