Comment 0 for bug 139949

Binary package hint: linux-source-2.6.22

Hi,

some apps can use the RTC in order to optimize video playback to avoid tearing, etc. For MythTV and MPlayer, /dev/rtc/max-user-freq should be set to 1024 to enable this functionality. However, it's set to 64 by default. MYthTV will fall back on a worse video timing method.

Here's an excerpt from the MythTV wiki on this matter:

"If MythTV will be using the RTC to time the display, it will usually request a high interrupt frequency, allowing it to time frames more precisely. However, unless MythFrontend is a privileged process, the highest frequency that it can request by default is 64 Hz. This is usually not sufficient for CRT monitors that are often set to a higher frequency, usually 85 or 100 Hz, as well as some LCD screens and projectors that can accept various frequencies, producing the tearing artifacts as mentioned earlier. The most common solution is simply to increase the maximum frequency that an unprivileged process can request from the RTC."

IMHO, /dev/rtc/max-user-freq should be set to 1024 by default. I tried to set dev/hpet/max-user-freq because HPET seems to be the way to go nowadays, but that didn't work. I still had to set /dev/rtc/max-user-freq to 1024 to make MythTV work with RTC video timing.