Re: writing/finding pci bar0
- From: gobo20@xxxxxxxxx
- Date: 26 Oct 2006 05:20:09 -0700
Tim Roberts wrote:
No. The BAR addresses are assigned by the BIOS at boot time, and possibly
modified later by the Linux kernel.
i understand the bios sets the five base addr's initially. but if the
kernel can change
them, why can't i (using setpci for example)?
when i look a the output of lspci -bvx, the value stored at
offset 0x10 is one higher than the actual base address. why
is this?
The low-order bit of the BAR registers say whether the address is in memory
space (0) or I/O port space (1). Parallel ports use I/O ports. That's why
you're able to tickle it from user mode (using outpb, right?). If it was a
memory address, you'd need to use a kernel driver.
interesting. after all the digging i've done, i did not come across
that little
detail. writing to the ports with outb.
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
.
- Follow-Ups:
- Re: writing/finding pci bar0
- From: Tim Roberts
- Re: writing/finding pci bar0
- References:
- writing/finding pci bar0
- From: gobo20
- Re: writing/finding pci bar0
- From: Tim Roberts
- writing/finding pci bar0
- Prev by Date: Re: writing to syslog file
- Next by Date: pci details for software writers
- Previous by thread: Re: writing/finding pci bar0
- Next by thread: Re: writing/finding pci bar0
- Index(es):
Relevant Pages
|
