[Intel-gfx] [PATCH v2] drm/i915: set minimum CD clock to twice the BCLK.

[Ville Syrjälä]

On Mon, Apr 09, 2018 at 03:11:38PM -0700, Kumar, Abhay wrote:
> 
> 
> On 4/9/2018 3:33 AM, Ville Syrjälä wrote:
> > On Fri, Apr 06, 2018 at 04:47:08PM +0300, Jani Nikula wrote:
> >> On Thu, 05 Apr 2018, Abhay Kumar <abhay.kumar at intel.com> wrote:
> >>> In glk when device boots with 1366x768 panel, HDA codec doesn't comeup.
> >>> This result in no audio forever as cdclk is < 96Mhz.
> >>> This chagne will ensure CD clock to be twice of  BCLK.
> >> In short, we can't poke around CDCLK like this. It needs a full modeset,
> >> and it's non-trivial from the path you're calling this from.
> > I tried to cobble something together quickly:
> > git://github.com/vsyrjala/linux.git glk_cnl_cdclk_audio
> >
> > Not tested at all, and I have no idea if my assumptions about
> > snd_hda_intel actually hold.
> Hi Ville,
> 
>      Tried your patch but as soon as it enters "glk_force_audio_cdclk" 
> the device locks up and reboots.  waited for 30-40 times and it always 
> reboot at same place.
> It never reaches Chrome OS login screen.

That likely means my assumptions about snd_hda_intel weren't true.
So probably we'll need to perform some surgery on snd_hda_intel
as well.

-- 
Ville Syrjälä
Intel OTC