On Tue, Oct 03, 2017 at 12:06:09AM -0700, Rodrigo Vivi wrote: > From: "Kahola, Mika" <[email protected]> > > Display Voltage and Frequency Switching (DVFS) is used to adjust the > display voltage to match the display clock frequencies. To save power the > voltage is set to minimum when disabling PLL. > > The sequence before frequency change is the following and it requests > the power controller to raise voltage to maximum > > - Ensure any previous GT Driver Mailbox transaction is complete. > - Write GT Driver Mailbox Data Low = 0x3. > - Write GT Driver Mailbox Data High = 0x0. > - Write GT Driver Mailbox Interface = 0x80000007. > - Poll GT Driver Mailbox Interface for Run/Busy indication cleared (bit 31 = > 0). > - Read GT Driver Mailbox Data Low, if bit 0 is 0x1, continue, else restart > the sequence. > Timeout after 3ms > > The sequence after frequency change is the following and it requests > the port controller to lower voltage to the minimum. > > - Write GT Driver Mailbox Data Low = 0x0 > - Write GT Driver Mailbox Data High = 0x0. > - Write GT Driver Mailbox Interface = 0x80000007. > > v2: reuse Paulo's work on cdclk. This patch depends on Paulo's patch > [PATCH 02/12] drm/i915/cnl: extract cnl_dvfs_{pre,post}_change > v3: (By Rodrigo): Fix typo on Paulo's name. > > Cc: Paulo Zanoni <[email protected]> > Cc: Ville Syrjälä <[email protected]> > Signed-off-by: Kahola, Mika <[email protected]> > Signed-off-by: Rodrigo Vivi <[email protected]>
Reviewed-by: Manasi Navare <[email protected]> Manasi > --- > drivers/gpu/drm/i915/intel_dpll_mgr.c | 14 ++++++-------- > 1 file changed, 6 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c > b/drivers/gpu/drm/i915/intel_dpll_mgr.c > index 6030fbafa580..a71a6c396bbd 100644 > --- a/drivers/gpu/drm/i915/intel_dpll_mgr.c > +++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c > @@ -2058,6 +2058,7 @@ static void cnl_ddi_pll_disable(struct drm_i915_private > *dev_priv, > struct intel_shared_dpll *pll) > { > uint32_t val; > + int ret; > > /* > * 1. Configure DPCLKA_CFGCR0 to turn off the clock for the DDI. > @@ -2067,11 +2068,9 @@ static void cnl_ddi_pll_disable(struct > drm_i915_private *dev_priv, > /* > * 2. If the frequency will result in a change to the voltage > * requirement, follow the Display Voltage Frequency Switching > - * Sequence Before Frequency Change > - * > - * FIXME: (DVFS) is used to adjust the display voltage to match the > - * display clock frequencies > + * (DVFS) Sequence Before Frequency Change > */ > + ret = cnl_dvfs_pre_change(dev_priv); > > /* 3. Disable DPLL through DPLL_ENABLE. */ > val = I915_READ(CNL_DPLL_ENABLE(pll->id)); > @@ -2089,11 +2088,10 @@ static void cnl_ddi_pll_disable(struct > drm_i915_private *dev_priv, > /* > * 5. If the frequency will result in a change to the voltage > * requirement, follow the Display Voltage Frequency Switching > - * Sequence After Frequency Change > - * > - * FIXME: (DVFS) is used to adjust the display voltage to match the > - * display clock frequencies > + * (DVFS) Sequence After Frequency Change > */ > + if (ret == 0) > + cnl_dvfs_post_change(dev_priv, 0); > > /* 6. Disable DPLL power in DPLL_ENABLE. */ > val = I915_READ(CNL_DPLL_ENABLE(pll->id)); > -- > 2.13.5 > > _______________________________________________ > Intel-gfx mailing list > [email protected] > https://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
