On Sat, Feb 16, 2019 at 09:47:13PM +0100, Harald Geyer wrote: > Hi Torsten! > > Torsten Duwe writes: > > > > > > > > But we need a way to control the mux from userspace and aside from > > > > > > > unbinding the ideas proposed thus far are: > > > > > > > > > > > > > > a) control the gpio directly > > > > > > > b) control the gpio via leds-gpio > > > > > > > > > > > > > > (a) was dismissed because we can't set a default from DT > > > > > > > (b) was dismissed because some rogue app might try to blink it > > > > Hey, this is a debugging hack. If some rogue app tries to blink it, so be it. > > > > > I suspect some distributions will pick up the patch I posted anyway, if > > > it doesn't get merged mainline. (This is how I forgot missing backlight > > > support - it just worked for too many people ...) If we ship > > > sun50i-a64-teres-i.dts with the proper nodes (but disabled), their > > > patches will be much easier to maintain as the official DT evolves. > > > > As I wrote (held by the list admin), I consider the whole console mux > > GPIO an U-Boot hack, and would put it into sun50i-a64-teres-i-u-boot.dtsi. > > (As a LED, see above :-) > > The thing is, one of the quite strict rules in kernel development is: > Never break userspace. That means: If we provide a way to userspace to > do something (ie switch between debug and audio), we are expected to > keep it around forever. So since there is a decent chance that someday > somebody might write a driver that handles this situation properly, we > don't want chain ourselves to some dirty hack. > > (I'm not totally against writing such a driver myself, if there are > enough use cases. However, I think that TERES alone is not enough.) > > > Would you care to submit a patch version without that GPIO handled? > > I think it's very useful and has the potential to be agreed upon. > > That would enable audio from the internal speakers but select debug > output on the HP jack by default. I would be okay with that, despite > still thinking that audio on the head phones should be the default. > > Maxime and Wens are the maintainers, so it's their call in the end. At this point, I'm not really convinced by the solution in that patch, but I don't have really good ideas either. I think it would be good to discuss this with Mark and Linus Walleij, they will probably have way better solutions than what I can come up with. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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