Hello, I am noticing some X problems (slow, crashes once and a while) on the RCA RM4100. I think this is related to the crazy way coreboot setup the mtrr. For some reason when the Intel onboard graphics are enabled, coreboot sets up this crazy looking mtrr. I don't think they should all be write-back? Isn't write-combining faster for graphics? Does it need to have a uncachable area?
coreboot onboard graphics disabled [root@localhost ~]# cat /proc/mtrr reg00: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1
coreboot onboard graphics enabled [root@localhost ~]# cat /proc/mtrr reg00: base=0x00000000 ( 0MB), size= 64MB: write-back, count=1 reg01: base=0x04000000 ( 64MB), size= 32MB: write-back, count=1 reg02: base=0x06000000 ( 96MB), size= 16MB: write-back, count=1 reg03: base=0x07000000 ( 112MB), size= 8MB: write-back, count=1
factory bios onboard graphics enabled [root@localhost ~]# cat /proc/mtrr reg00: base=0x07800000 ( 120MB), size= 8MB: uncachable, count=1 reg01: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1 reg02: base=0xf0000000 (3840MB), size= 128MB: write-combining, count=3
On Wed, Apr 16, 2008 at 5:03 PM, joe@settoplinux.org wrote:
Hello, I am noticing some X problems (slow, crashes once and a while) on the RCA RM4100. I think this is related to the crazy way coreboot setup the mtrr. For some reason when the Intel onboard graphics are enabled, coreboot sets up this crazy looking mtrr. I don't think they should all be write-back? Isn't write-combining faster for graphics? Does it need to have a uncachable area?
that is normal.
reg00: base=0x00000000 ( 0MB), size= 64MB: write-back, count=1 reg01: base=0x04000000 ( 64MB), size= 32MB: write-back, count=1 reg02: base=0x06000000 ( 96MB), size= 16MB: write-back, count=1 reg03: base=0x07000000 ( 112MB), size= 8MB: write-back, count=1
==
reg00: base=0x07800000 ( 120MB), size= 8MB: uncachable, count=1 reg01: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1
and old kernel like previous one 64+32+16+8 == (128 - 8)
YH
Hey did anyone know you can adjust your mtrr in Linux? I did not know that:-) Check out this link:
http://www.meduna.org/txt_mtrr_en.html
Thanks, Joseph Smith Set-Top-Linux www.settoplinux.org
-----Original Message----- From: yhlu [mailto:yinghailu@gmail.com] Sent: Wednesday, April 16, 2008 10:08 PM To: joe@settoplinux.org Cc: coreboot@coreboot.org Subject: Re: [coreboot] Crazy Intel graphics mtrr
On Wed, Apr 16, 2008 at 5:03 PM, joe@settoplinux.org wrote:
Hello, I am noticing some X problems (slow, crashes once and a while) on the
RCA RM4100. I think this is related to the crazy way coreboot setup the mtrr. For some reason when the Intel onboard graphics are enabled, coreboot sets up this crazy looking mtrr. I don't think they should all be write-back? Isn't write-combining faster for graphics? Does it need to have a uncachable area?
that is normal.
reg00: base=0x00000000 ( 0MB), size= 64MB: write-back, count=1 reg01: base=0x04000000 ( 64MB), size= 32MB: write-back, count=1 reg02: base=0x06000000 ( 96MB), size= 16MB: write-back, count=1 reg03: base=0x07000000 ( 112MB), size= 8MB: write-back, count=1
==
reg00: base=0x07800000 ( 120MB), size= 8MB: uncachable, count=1 reg01: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1
and old kernel like previous one 64+32+16+8 == (128 - 8)
YH
-
Joe -
joe＠settoplinux.org
-
yhlu