[brddd]

Is it recommended to use 8 Rx DMA rings for the CrystalHD driver running on Ubuntu 8.0.4 on AppleTV hardware? I am using XBMC Dharma RC1.

Based on numerous tests, the only successful configuration that works for me is using r174 of the crystalhd driver, but with 8 Rx DMA rings instead of 16. I see various revisions changing it to 8, then reverting back to 16.

When using 16 with my setup I get video/audio sync issues only when I pause or fast forward content. For video it drops frames, and audio is out of sync. However, a start from the beginning content is fine if you don't pause or fast-forward.

With 8, I don't have these issues, 1080p content even plays fine, which is a first for me. It always dropped frames previously. I am quite happy now!

I'm going to stick with 8 Rx DMA rings, and wanted to share this tip in case others have had similar issues.

Modify bc_dts_glob_lnx.h changing this line to 8 instead of 16:
BC_RX_LIST_CNT = 16, /* Max Rx DMA Rings*/

[m_lopez_h]

Modify bc_dts_glob_lnx.h changing this line to 8 instead of 16:
BC_RX_LIST_CNT = 16, /* Max Rx DMA Rings*/

I'd like to try this out. Where is the location of the file?

[brddd]

I'd like to try this out. Where is the location of the file?

It is located at: crystalhd-for-osx-read-only/crystalhd/include/bc_dts_glob_lnx.h

[dan1son]

This only applies to Linux and only if you're downloading and compiling your own kernel driver and libraries. The ATV kext files are still using 8 as far as I know.

I'm running 8 on mine and have been having good luck with it.