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HDMI audio on Evergreen (RE)
HDMI audio on Evergreen (RE)
Last thursday I've received my Asus 1215B which is based on AMD-E450 CPU. It comes with integrated Radeon HD6320 which is a Palm chip (Evergreen family and 1002:9806 in my case). Late friday I've installed openSUSE and on saturnday I've started hacking on HDMI audio.
I installed fglrx, hacked radeontool utility to read all registers and started looking at the dumps. There comes the great news... It took me about 24 hours (and dozens of lokcups) to add hackish support for HDMI audio in my model :)
I'll release RFC patches in a moment, but I've also a request. To make this work on all Evergreen cards I need debuggers/testers with:
1) Evergreen GPU
2) Audio capable TV/monitor
3) Knowledge to checkout, modify and compile radeontool
4) Courage to install fglrx -
b43: fixed DMA on some (Mini PCI) cards
Recently I've sent two important patches to John:
ssb: fix DMA translation for some specific boards
b43: fix DMA on some bugged hardware
(both are already in wireless-next, waiting for kernel 3.2 merge window).
They have fixed DMA transfers on some specific cards like my 14e4:4329 which is N-PHY based card using Mini PCI slot. -
Thank You Poznan University of Technology
As you should know, I'm involved in Broadcom-related Linux development ─ some time ago I've added support for 802.11n Broadcom chipset named BCM4321. Unfortunately it took me a lot of time and the support wasn't really complete. I've done all the work in my free time and I still had to be focused on my studies. Luckily, Poznan University of Technology (the university I study at), noticed my efforts and valued it! They proposed me to continue my contribution to the b43 project as part of my MSc work! This allowed me to spend a lot of time on Broadcom cards drivers :)
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Improvements in b43 for N-PHY rev 3+
Earlier tests have shown we can not transmit on OFDM rates in case of 14e4:432b (PHY rev 4). Fortunately fix was really easy, we were just missing static tables for higher revisions. Adding it allowed TX on 54M rate, 11M is not maximum anymore :)
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First b43 N-PHY benchmarks and improvements
From the first moment of enabling support for N-PHYs devices we were suffering from PHY errors and low TX performance. Fortunately some quick tests has shown that forcing rate to some of CCK values (1M, 2M, 5.5M, 11M) silences most of the PHY errors. On the other hard switching to any OFDM rate (anything except 1/2/5.5/11) stops transmission completely and produces PHY errors. So we knew that our two problems were related and we got some clue.
The good news is that Larry figured out that there is some special field in TX header that should be correctly filled for LP-PHY and N-PHY devices. The great news is that implementing support for filling this field made OFDM transmission possible :) So with the patch that was just submitted to linux-wireless, we can finally achieve some normal speeds with b43 :)
As part of testing my patch I made some benchmarks for clean b43, patched b43 and wl 5.100.82.38. See the charts for results.