Re: [PATCH] ath9k: fix build error with LEDS_CLASS=m

[Johannes Berg]

On Wed, 2021-01-27 at 12:35 +0200, Kalle Valo wrote:
> Arnd Bergmann <arnd@xxxxxxxxxx> writes:
> 
> > On Mon, Jan 25, 2021 at 4:04 PM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> > > On Mon, 25 Jan 2021 at 15:38, Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
> > > > On Mon, Jan 25, 2021 at 2:27 PM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> > > 
> > > I meant that having MAC80211_LEDS selected causes the ath9k driver to
> > > toggle on/off the WiFi LED. Every second, regardless whether it's
> > > doing something or not. In my setup, I have problems with a WiFi
> > > dongle somehow crashing (WiFi disappears, nothing comes from the
> > > dongle... maybe it's Atheros FW, maybe some HW problem) and I found
> > > this LED on/off slightly increases the chances of this dongle-crash.
> > > That was the actual reason behind my commits.
> > > 
> > > Second reason is that I don't want to send USB commands every second
> > > when the device is idle. It unnecessarily consumes power on my
> > > low-power device.
> > 
> > Ok, I see.
> > 
> > > Of course another solution is to just disable the trigger via sysfs
> > > LED API. It would also work but my patch allows entire code to be
> > > compiled-out (which was conditional in ath9k already).
> > > 
> > > Therefore the patch I sent allows the ath9k LED option to be fully
> > > choosable. Someone wants every-second-LED-blink, sure, enable
> > > ATH9K_LEDS and you have it. Someone wants to reduce the kernel size,
> > > don't enable ATH9K_LEDS.
> > 
> > Originally, I think this is what CONFIG_MAC80211_LEDS was meant
> > for, but it seems that this is not actually practical, since this also
> > gets selected by half of the drivers using it, while the other half have
> > a dependency on it. Out of the ones that select it, some in turn
> > select LEDS_CLASS, while some depend on it.
> > 
> > I think this needs a larger-scale cleanup for consistency between
> > (at least) all the wireless drivers using LEDs.
> 
> I agree, this needs cleanup.
> 
> > Either your patch or mine should get applied in the meantime, and I
> > don't care much which one in this case, as we still have the remaining
> > inconsistency.
> 
> My problem with Krzysztof's patch[1] is that it adds a new Kconfig
> option for ath9k, is that really necessary? Like Arnd said, we should
> fix drivers to use CONFIG_MAC80211_LEDS instead of having driver
> specific options.
> 
> So I would prefer take this Arnd's patch instead and queue it for v5.11.
> But as it modifies mac80211 I'll need an ack from Johannes, what do you
> think?

Sure, that seems fine.

Acked-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>

johannes