On Thu, Sep 24, 2015 at 02:50:16PM +0200, Patrik Jakobsson wrote: > On Wed, Sep 23, 2015 at 01:18:00PM +0200, Patrik Jakobsson wrote: > > On Wed, Sep 23, 2015 at 10:43:00AM +0200, Daniel Vetter wrote: > > > On Mon, Sep 21, 2015 at 10:00:45AM +0200, Patrik Jakobsson wrote: > > > > On Wed, Sep 16, 2015 at 11:10:07PM +0300, Ville Syrjälä wrote: > > > > > On Fri, Sep 11, 2015 at 01:55:22PM +0200, Patrik Jakobsson wrote: > > > > > > We need to be able to control if DC6 is allowed or not. Much like > > > > > > requesting power to a specific piece of the hardware we need to be able > > > > > > to request that we don't enter DC6 during certain hw access. > > > > > > > > > > > > To solve this without introducing too much infrastructure I'm hooking > > > > > > into the power well / power domain framework. DC6 prevention is modeled > > > > > > much like an enabled power well. Thus I'm using the terminology on/off > > > > > > for DC states instead of enable/disable. > > > > > > > > > > > > The problem that started this work is the need for DC6 to be disabled > > > > > > when accessing DP_AUX_A during CRTC on/off. That is also fixed in this > > > > > > patch. > > > > > > > > > > > > This is posted as an RFC since DMC and DC state handling is being > > > > > > reworked and will possibly affect the outcome of this patch. The patch > > > > > > has known warnings. > > > > > > > > > > > > Signed-off-by: Patrik Jakobsson <patrik.jakobsson@xxxxxxxxxxxxxxx> > > > > > > --- > > > > > > drivers/gpu/drm/i915/intel_ddi.c | 9 +++++ > > > > > > drivers/gpu/drm/i915/intel_drv.h | 2 + > > > > > > drivers/gpu/drm/i915/intel_runtime_pm.c | 69 +++++++++++++++++++++++++-------- > > > > > > 3 files changed, 64 insertions(+), 16 deletions(-) > > > > > > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c > > > > > > index 4823184..c2c1ad2 100644 > > > > > > --- a/drivers/gpu/drm/i915/intel_ddi.c > > > > > > +++ b/drivers/gpu/drm/i915/intel_ddi.c > > > > > > @@ -2288,6 +2288,8 @@ static void intel_ddi_pre_enable(struct intel_encoder *intel_encoder) > > > > > > if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP) { > > > > > > struct intel_dp *intel_dp = enc_to_intel_dp(encoder); > > > > > > > > > > > > + intel_display_power_get(dev_priv, POWER_DOMAIN_AUX_A); > > > > > > + > > > > > > > > > > These I think shouldn't be necessary with my > > > > > intel_display_port_aux_power_domain() stuff since intel_dp_aux_ch() will > > > > > itself grab the appropriate power domain. > > > > > > > > > > That's of course assuming that AUX is the only reason why we need to > > > > > keep DC6 disabled here. > > > > > > > > > > > > > The upside with having get/put around bigger aux transfers is that we don't get > > > > tons of enable/disable lines in the log. My vote is that we keep this but also > > > > have your fine-grained get/puts. > > > > > > Imo the correct solution to avoid this is by adding a slight bit of > > > hystersis to the power well code. Which means that yes, we reinvent > > > another feature of the core power_domain code in our home-grown solution - > > > I hate it when my years old predictions come true ;-) > > > > > > Sprinkling higher-level get/put calls all over the place is imo just > > > leaking the abstraction, which isn't good. > > > -Daniel > > > > With Ville's patches the problem is not as bad as I first thought. We can add > > hysteresis later if needed. > > > > -Patrik > > So I discovered that we cannot have DC5 and DC6 as seperate power wells since > they are mutually exclusive. As Ville pointed out we don't use DC5 for anything > so we could get away for now with just DC6 as a power well. > > As I see it there are three ways to go about this: > > A. Add AUX A to Power well 2. > This would power up PW2 during DP Aux A even though we don't need it but since > we get the side effect of DC6 being disabled it should work. > > B. Add DC6 off as a power well and remove DC5 off. > Fairly straight forward but assumes we don't need DC5 control. > > C. Add multi-state support for the DC power well. > Would be the nice way but perhaps a bit overkill. Good thing about this would be > that we can incorporate DC9 control for BXT and unify more of the DC code. > > So A, B or C? After some spitballing with Imre we came up with the following power well layout, which I think matches the documented seuqences in the spec the best: display well: domains: all enable: init display sequence enable pch reset handshake enable pw1 and miscio enable cdclk pll enable dbuf dc_state_en = up_to_dc6 disable: dc_state_en = disable uninit display sequence disable dbuf disable cdclk pll disable pw1 and miscio dc6 off well: domains: gmbus, dc5 off well domains enable: dc_state_en = up_to_dc5 disable: dc_state_en = up_to_dc6 dc5 off well: domains: aux A, pw2 well domains enable: dc_state_en = disable disable: dc_state_en = up_to_dc5 pw2 well: domains: ddi B/C/D/E, aux B/C/D/E, vga, audio, pipe B/C, pfit B/C enable: enable pw2 disable: disable pw2 -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx