On Saturday 19 December 2015 01:02:53 Darren Hart wrote: > On Thu, Dec 17, 2015 at 07:54:35PM +0100, Hans de Goede wrote: > > Hi, > > > > On 17-12-15 19:47, Pali Rohár wrote: > > >Hi Hans! See my comments below about your patches. > > ... > > > >>@@ -159,7 +157,8 @@ static void dell_wmi_process_key(int > > >>reported_key) > > >> > > >> /* Don't report brightness notifications that will also come > > >> via ACPI */ if ((key->keycode == KEY_BRIGHTNESSUP || > > >> > > >>- key->keycode == KEY_BRIGHTNESSDOWN) && acpi_video) > > >>+ key->keycode == KEY_BRIGHTNESSDOWN) && > > >>+ acpi_video_handles_brightness_key_presses()) > > > > > >I do not like this, because that function uses mutex and is called > > >every time when brightness key event is received by wmi notify > > >handler. > > > > Right and this is going to happen 1000-s of times a second so is > > really going to be a performance problem (not). > > > > We cannot cache the return value as was being done before because > > it can change during startup depending in module loading order > > (the old code actually got this somewhat wrong), and taking a > > mutex in a code-path which gets executed only once a second tops > > is really a non issue. > > Right, this is not a hot path, so the mutex is, indeed, not an issue. Ok. -- Pali Rohár pali.rohar@xxxxxxxxx
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