On Mon, Jun 25, 2018 at 11:53:59AM +0200, Takashi Iwai wrote: > On Mon, 25 Jun 2018 11:23:17 +0200, > Sriram Periyasamy wrote: > > > > On Mon, Jun 25, 2018 at 11:08:13AM +0200, Takashi Iwai wrote: > > > On Mon, 25 Jun 2018 10:53:49 +0200, > > > Sriram Periyasamy wrote: > > > > > > > > On Fri, Jun 22, 2018 at 07:14:50PM +0200, Takashi Iwai wrote: > > > > > On Fri, 22 Jun 2018 18:42:24 +0200, > > > > > Pierre-Louis Bossart wrote: > > > > > > > > > > > > On 6/22/18 4:25 AM, Sriram Periyasamy wrote: > > > > > > > On certain platforms, Display HDMI HDA codec was not going to sleep state > > > > > > > after the use when links are powered down after turning off the display > > > > > > > power. As per the HW recommendation, links are powered down before turning > > > > > > > off the display power to ensure that the codec goes to sleep state. > > > > > > > > > > > > The change looks ok, I am still not clear on display power > > > > > > management. snd_hdac_display_power is called both from hdac_hdmi.c and > > > > > > skl.c in the respective probe/suspend/resume routines, wondering if > > > > > > this is redundant or intentional. > > > > > > > > > > Yeah, it looks like that skl.c keeps the display power on by assuming > > > > > that it's turned off by the codec driver, but it doesn't happen > > > > > actually. I also find it fishy there... > > > > > > > > > > > > > snd_hdac_display_power is called intentionally to ensure that the codec is > > > > powered up before any communication is initiated from either skl.c or > > > > hdac_hdmi.c. > > > > > > But who turns it down if the device is not used? > > > > Powering down of codec is taken care in codec's suspend routine. > > But you'll power up twice, no? Once in skl_resume() (which is no > runtime resume but only for S3/S4) and once in codec resume. > I wonder who will turn down when you wake up from S3. No. When entering to S3, hdmi_codec_prepare() will invoke the runtime resume of codec hdac_hdmi_runtime_resume() which power up the codec and skl_suspend power down the codec. When it wakes up from S3, skl_resume() powers up the codec and hdmi_codec_complete invokes the runtime suspend of codec hdac_hdmi_runtime_suspend() which powers down the codec. This design is required to achieve the runtime power reference count for codec device when it is put to S3/S4 while playback was going on. > The runtime > suspend doesn't call snd_hdac_display_power() in skl.c. > Display power management for all runtime uses cases are handled in the codec driver hdac_hdmi.c. Thanks, Sriram. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
