On 08/29/2011 10:51 AM, Colin Guthrie wrote: > 'Twas brillig, and David Henningsson at 29/08/11 08:04 did gyre and gimble: >> On 08/26/2011 03:05 PM, Colin Guthrie wrote: >>> 'Twas brillig, and Colin Guthrie at 25/08/11 17:17 did gyre and gimble: >>>> 'Twas brillig, and Arun Raghavan at 25/08/11 17:08 did gyre and gimble: >>>>> On Wed, 2011-08-24 at 22:58 +0100, Colin Guthrie wrote: >>>>>> Hi, >>>>>> >>>>>> This is a patch set that will likely mostly interest David, but also >>>>>> solves one of the remaining niggles I have for 1.0 - the fact that >>>>>> volumes are not set properly on port changes. >>>>>> >>>>>> Now this only "solves" that niggle when the module-device-restore >>>>>> is used, >>>>>> but I'm happy enough to rely on that for now seeing as it's the >>>>>> default >>>>>> on 99.999% of desktop installs. >>>>>> >>>>>> The overall benefit of this patch is that it allows different volumes >>>>>> to be saved and restored for different ports. Combine this with >>>>>> David's >>>>>> work on making jack-detection work (which triggers port changes) >>>>>> and you >>>>>> automatically get different volumes on headphones vs. speakers. >>>>> >>>>> My main concern is the following scenario: >>>>> >>>>> 0. Say we start with built-in speaker and headphone port and equal >>>>> (maybe 70%) volume >>>>> 1. With headphones plugged in, I've got the volume turned up while >>>>> playing something that's naturally not very loud >>>>> 2. I pull out headphones, start playing something that's quite loud, I >>>>> turn down the volume >>>>> 3. I put the headphones back, find the output too loud (since the port >>>>> volume was turned up for the previous stream) >>>>> >>>>> While the current scenario isn't ideal, it's easy for users to wrap >>>>> their head around (different devices have different loudness >>>>> levels). If >>>>> we don't handle this sort of case in the per-port-volume case, IMO the >>>>> behaviour is potentially confusing/frustrating to users. >>>>> >>>>> Maybe there's a simple way to handle this that I'm missing ... >>>> >>>> I'm not sure there is a way to handle this really. Either we want >>>> volumes per-port or we don't. IMO we do (this is how it works on my >>>> iPhone for example) and I think from the various mumblings I've heard >>>> over the years most people want this type of functionality. >>>> >>>> But perhaps there is indeed some magic solution that we are both >>>> missing :p >>> >>> Anyone else got any comments on this? I'd like to push it out if all is >>> well otherwise. >>> >>> >>> FWIW, to address Arun's concern somewhat, we could relatively easily >>> make a change here that kept the same volume for every port simply by >>> changing the key name used and then expose this as a module argument >>> should people really hate this behaviour. >>> >>> Any comments on the code would be appreciated too :) >> >> Well, I'm not that much into the database format, so can't really look >> for bugs there...I have a question though: What about loudness bumps? It >> looks like that could be the effect if you set the volume in such a >> reactive fashion? > > Well if you plug in a jack, you kinda expect the volume to change anyway > (it's a different physical thing outputting the sound. > > Not really sure what you're meaning by loudness bumps in this respect. > Sure it's possible that the user configures things such that things get > too loud when they unplug things, but I'm not convinced there is a way > around that while still supporting independent volumes for headphones > vs. speakers. Assume we have a card with one ALSA kcontrol named "Master" that controls both headphone and speaker volume. User likes to have volume at -6 dB with headphones and -24 dB with speakers. When user unplugs headphones, he will have -6 dB in his speakers from the point when the kernel does the automute stuff until we have synced the volume, i e a "bump" in the volume. In that case, I'm not sure if there's anything we could do about it. But this also happens when you switch manually, in which case which *could* do something about it. My point is that a port switch essentially a change of ALSA kcontrols, and it seems like the proposed implementation would do the change in two steps, first in reaction to the port switch, then in reaction to module-device-restore. And there should be possible to do it in one step only and set the right volume at the same time as you set the port switch. Do you follow? > > There could be some kind of heuristics applied - e.g. if there are some > active streams, perhaps we should ramp up the volume to it's previous > value over a couple seconds giving some time for the user to hit the > volume down buttons. That said, I'm not convinced this would really help > (and we've not yet got nice volume ramping anyway!). > > Other methods such as erring on the side of caution and keeping the > volume low, but giving the user an option to restore the previous volume > via some UI feedback. But I don't think the infrastructure is quite > there yet (nor am I convinced this is a good idea generally). > > Other thoughts on the issue are welcome tho'. > >> However - it might be that there is no true way around that anyway, as >> in the case of jack detection as we're only reactive to what the kernel >> does. > > That's my gut feeling but I'd be happy to consider anything that makes > for a better user experience overall. > > Col > > -- David Henningsson, Canonical Ltd. http://launchpad.net/~diwic
