[mythtv] Driver buffers overflowed on one channel

[ccljacobson at comcast.net]

All,

I've been running MythTV on my new HTPC for about a month now and one of the nagging problems that I still have is that one HDTV channel, KTVD-DT in Denver, doesn't come in correctly.  All other are good.  It takes a little longer for MythTV to tune in the channel.  Once it's going, it will play for a second and then pause for a couple seconds.  Also, during this time there are visual artifacts (or glitches) and sometimes only a partial image is shown.  This is true regardless of live or recorded TV.  Hitting F7 while watching the channel says that the signal is 85 to 90 percent.

With the same antenna configuration, I've been able to watch this channel without problem in both Kaffeine on Linux and BeyondTV on Windows XP.

I'm using the atrpms.net RPMs on FC 6 and I've tried both the 0.20 stable and several versions of the 0.21 trunk RPMs without any noticeable difference.  

One thing that I see in the mythbackend.log are many messages like the following:
2007-02-25 11:05:20.179 DevRdB(1) Error: Driver buffers overflowed
2007-02-25 11:05:23.344 DevRdB(1) Error: Driver buffers overflowed
2007-02-25 11:05:26.507 DevRdB(1) Error: Driver buffers overflowed
2007-02-25 11:05:29.670 DevRdB(1) Error: Driver buffers overflowed

My uptime is rather low:
 11:09:03 up 15:40,  1 user,  load average: 0.70, 0.52, 0.30

The disk utilization is rather low as well (md2 contains the LiveTV recordings and goes across sd[a-d]):
# iostat -dmx 10 2
Linux 2.6.19-1.2895_0.99.fc6.cubbi_suspend2_8k (localhost.localdomain)  02/25/2007

Device:         rrqm/s   wrqm/s   r/s   w/s    rMB/s    wMB/s avgrq-sz avgqu-sz   await  svctm  %util
sda              14.49    14.69  6.36  3.25     0.09     0.07    34.27     0.05    5.32   3.02   2.91
sdb              16.21    14.66  6.68  3.27     0.10     0.07    34.79     0.05    5.16   2.91   2.89
sdc              14.33    15.42  6.33  3.30     0.09     0.08    34.55     0.05    5.67   3.07   2.96
sdd               0.00     0.00  0.00  0.00     0.00     0.00    15.89     0.00    3.48   2.93   0.00
md0               0.00     0.00  2.84  6.48     0.03     0.03    11.76     0.00    0.00   0.00   0.00
md2               0.00     0.00  9.87 26.05     0.18     0.10    15.86     0.00    0.00   0.00   0.00
md1               0.00     0.00  0.00  0.00     0.00     0.00     8.00     0.00    0.00   0.00   0.00

Device:         rrqm/s   wrqm/s   r/s   w/s    rMB/s    wMB/s avgrq-sz avgqu-sz   await  svctm  %util
sda               3.10    33.97  2.20  7.09     0.02     0.17    42.32     0.11   12.15   9.75   9.06
sdb              10.99    27.47  0.50  5.19     0.04     0.14    65.82     0.08   14.84  10.26   5.84
sdc               7.89    31.97  2.60  6.49     0.04     0.16    45.80     0.17   18.93  11.13  10.12
sdd               0.00     0.00  0.00  0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00
md0               0.00     0.00  0.60  7.59     0.00     0.03     8.39     0.00    0.00   0.00   0.00
md2               0.00     0.00  0.10 76.12     0.00     0.30     8.00     0.00    0.00   0.00   0.00
md1               0.00     0.00  0.00  0.00     0.00     0.00     0.00     0.00    0.00   0.00   0.00

Here's my current configuration:
Motherboard: Abit NF-M2
CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ (65W)
Memory: 2GB (4 x 512MB Corsair PC2 6400)
Hard Disk: 4 x 500GB SATA WD in Linux software RAID 5 EXT3
Tuners: 2 x Dvico FusionHDTV 5 USB
Linux: 2.6.19-1.2895_0.99.fc6.cubbi_suspend2_8k
MythTV: mythtv-0.21-154_trunk_r12854.fc6.at

Thank you in advance.

Lonny