DVD choppy

[Philip Walden]

Dotan Cohen wrote:
> On 30/01/07, Philip Walden <pwaldenlinux at pacbell.net> wrote:
>> Philip Walden wrote:
>> > Dotan Cohen wrote:
>> >> On a recent Dell laptop, what would cause DVD playback to be very
>> >> choppy?
>> > Besides the ATA DMA stuff, you may also want to check whether your
>> > MTRR is being set properly by the xorg X server.
>> >
>> > Mine looks like this:
>> >
>> > cat /proc/mtrr
>> > reg00: base=0x00100000 (   1MB), size= 256MB: write-back, count=1
>> > reg01: base=0xfc000000 (4032MB), size=  32MB: write-combining, count=1
>> >
>> > You should have at least one "write-combining" entry which means the
>> > graphics card is set properly. Otherwise, performance can drop
>> > dramatically.
>> Here is a howto:
>>
>> http://www.faqs.org/docs/Linux-HOWTO/DVD-HOWTO.html#ss6.1
>>
>
> Thanks. I've nothing in /proc/mtrr:
>
> [root at localhost ~]# ls /proc/mtrr
> /proc/mtrr

Try:
  cat /proc/mtrr
reg00: base=0x00100000 (   1MB), size= 256MB: write-back, count=1
reg01: base=0xfc000000 (4032MB), size=  32MB: write-combining, count=1


>
> However, I'm having a hard time starting X, as it's already running!
> I've combed the logs in /var/logs but I don't have those lines. When I
> kill X with CTRL-ALT-ESC it starts right back up automatically, not
> letting me redirect it's output to a file.
I found mine using lspci

# /sbin/lspci -v
  :
01:05.0 VGA compatible controller: nVidia Corporation NV5 [RIVA 
TNT2/TNT2 Pro] (rev 15) (prog-if 00 [VGA])
        Subsystem: ASUSTeK Computer Inc. AGP-V3800 SDRAM
        Flags: bus master, 66MHz, medium devsel, latency 40, IRQ 11
        Memory at f5000000 (32-bit, non-prefetchable) [size=16M]
        Memory at fc000000 (32-bit, prefetchable) [size=32M]       
<========== use the prefetchable
        Capabilities: [60] Power Management version 1
        Capabilities: [44] AGP version 2.0

I then added this to /etc/rc.local:

# set mtrr at least until Xorg 7.1 is added to the distribution
echo "base=0xfc000000 size=0x2000000 type=write-combining" >| /proc/mtrr


> Just for kicks, here's the output of "lspci -v" as suggested by the 
> same page:
   :
> 01:00.0 VGA compatible controller: ATI Technologies Inc Radeon
> Mobility X1400 (prog-if 00 [VGA])
>        Subsystem: Dell Unknown device 2003
>        Flags: bus master, fast devsel, latency 0, IRQ 4
>        Memory at d0000000 (32-bit, prefetchable) [size=256M]
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>        I/O ports at ee00 [size=256]
>        Memory at efdf0000 (32-bit, non-prefetchable) [size=64K]
>        [virtual] Expansion ROM at efd00000 [disabled] [size=128K]
>        Capabilities: [50] Power Management version 2
>        Capabilities: [58] Express Legacy Endpoint IRQ 0
>        Capabilities: [80] Message Signalled Interrupts: 64bit+
> Queue=0/0 Enable-
I would guess your's would look like:

echo "base=0xd0000000 size=0x10000000 type=write-combining" >| /proc/mtrr