On Fri, Jul 20, 2012 at 11:40 AM, RAHUL SHARMA <rahul.sha...@samsung.com> wrote: > > > ------- Original Message ------- > Sender : Lars-Peter Clausen<l...@metafoo.de> > Date : Jul 19, 2012 19:12 (GMT+05:30) > Title : Re: exynos drm hdmi audio: how to recieve audio parameters (sf, bps, > channel count) > > On 07/19/2012 02:22 PM, Rob Clark wrote: >> On Tue, Jul 17, 2012 at 1:12 AM, RAHUL SHARMA wrote: >>> hi, >>> >>> I am adding support for hdmi audio, inside exynos drm hdmi driver. Hdmi >>> audio is initialized with default parameters. I want to implement the >>> mechanism to update hdmi registers, whenever audio properties got changed >>> (i2s/spdif). raedon/r600 drm dirver is polling the audio ip every 100 ms >>> and reconfigure the hdmi audio block. This is not possible with exynos as >>> all information cannot be collected from i2s tx registers. It is directly >>> set on wm8994 connected through i2c. >>> Possible solution: >>> 1) drm driver exposing ioctl for setting audio parameters. >>> 2) alsa driver notifying the change in audio parameters through kernel >>> notifiers. drm hdmi driver subscribed for the same. >> >> I am certainly not an audio expert, but I am pretty sure something >> along the lines of solution #2 would be better. I don't think >> userspace would want to know about some exynos drm specific ioctls in >> order to make audio work. >> >> BR, >> -R > > > I don't know how the audio setup for exynos HDMI hardware looks like, so > this might not be applicable in this case. But what I did for HDMI > transmitter I was working on, is to register a ASoC codec device as a > subdevice to the HDMI transmitter. All access to the sound registers is done > from that subdevice and you don't need any special notifier hooks, since you > can use the normal alsa driver callbacks. > > It might be a good idea if you could describe how your setup looks exactly. > E.g. which components does the audio stream pass through, where does it > originate and how the different components related to each other. > > - Lars
Thanks Lars, Rob, Kyungmin, In exynos, i2s and spdif DAIs configure the i2s, spdif tx IP regs. In hw, I2s and spdif tx o/p pins are also connected to the i2s-In and spdif-In blocks of hdmi tx. Drm hdmi sub driver needs to configure the i2s-In and spdif-In blocks with the same setting as in i2s and spdif tx IPs. Hdmi is solely accessed by drm driver where hdmi is registered as a sub-driver along with lcd sub-driver. I hope, I am able to explain the flow and connections, through above. Lars, how can I refer your implementation where Adding 'hdmi audio' as a seperate subdrv. If I understand correctly, it will be exposed as a seperate sound card, parallel to i2s and spdif cards, which user app accesses and configure and about scenarios with hpd. Kyungmin, about adding ioctl; it looks clean, but as Rob stated, is it a right way as drm framework is primarily meant for gfx/video configurations? Please exaplin me this point. - Rahul Sharma _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel
