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. -- Darren Hart Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
