[mythtv] Remote Controls / Stability

[Grant Taylor]

> My chipset is a VIA KT266.  There are scattered reports of VIA's PCI
> implementation being awful; this article describes a bug that may very

So making the register changes described below does seem to have made
an improvement.  I can now run using mpeg4 at 480x480 without getting
jitter.  Larger resolutions still don't work, possibly due to my
conservative memory settings.

http://www.networking.tzo.com/net/software/readmes/techvl019d.htm

I translated this web page from English to Bourne Again, in case
anyone else wants to try this:

#! /bin/bash

dev='00:00:00'
go=false

r=0x76
echo -n $r: ' '
v=`pcitweak -b -r $dev $r`
s=$(( $v & ~ 0x30 | 0x10 ))	# set bits 5,4 to 01
printf '0x%02x => 0x%02x\n' $v $s
$go && pcitweak -w $dev -b `printf '0x%02x' $r` `printf '0x%02x' $s`

r=0x70
echo -n $r: ' '
v=`pcitweak -b -r $dev $r`
s=$(( $v | ( 1 << 2 ) ))		# set bit 2        ; PCI Master Read Caching
s=$(( $s | ( 1 << 1 ) | ( 1 << 3 ) ))	# set bit 1 and 3  ; PCI Delay Transaction
printf '0x%02x => 0x%02x\n' $v $s
$go && pcitweak -w $dev -b `printf '0x%02x' $r` `printf '0x%02x' $s`

r=0x94
echo -n $r: ' '
v=`pcitweak -b -r $dev $r`
s=$(( $v | ( 1 << 6 ) ))		# set bit 6        ; PCI Mas Rd Cac Probe T1 option
printf '0x%02x => 0x%02x\n' $v $s
$go && pcitweak -w $dev -b `printf '0x%02x' $r` `printf '0x%02x' $s`

r=0x75
echo -n $r: ' '
v=`pcitweak -b -r $dev $r`
s=$(( $v & ~ 0x0f ))		        # clear bits 3-0   ; PCI Arb Timer cleared
printf '0x%02x => 0x%02x\n' $v $s
$go && pcitweak -w $dev -b `printf '0x%02x' $r` `printf '0x%02x' $s`

r=0x4b
echo -n $r: ' '
v=`pcitweak -b -r $dev $r`
s=$(( ( $v & ~ 0xf0 ) | ( 1 << 7 ) ))	# bits 7-4 to 1000 ; UpCmds over VLink priority change
printf '0x%02x => 0x%02x\n' $v $s
$go && pcitweak -w $dev -b `printf '0x%02x' $r` `printf '0x%02x' $s`

r=0x42
echo -n $r: ' '
v=`pcitweak -b -r $dev $r`
s=$(( $v | ( 1 << 4 ) ))		# set bit 4        ; undocumented stabilization tweak
printf '0x%02x => 0x%02x\n' $v $s
$go && pcitweak -w $dev -b `printf '0x%02x' $r` `printf '0x%02x' $s`



--
Grant Taylor - gtaylor@picante.com - http://www.picante.com/~gtaylor/
    Linux Printing Website and HOWTO:  http://www.linuxprinting.org/