On Thu, Nov 15, 2018 at 11:48:06AM -0800, clinton.a.taylor@xxxxxxxxx wrote: > From: Clint Taylor <clinton.a.taylor@xxxxxxxxx> > > The calibration RCOMP value in PORT_TX_DW6 in stored in dev_priv during > driver init. Use this value instead of reading the register again as the > power well for PORTA RCOMP register may not be enabled and will return > 0xFFFFFFFF instead of the computed value. PORT_REF_DW6 for both the port A and the port B/C PHYs are in power well #0, which is always on whenever we are runtime resumed (which is always the case during _bxt_ddi_phy_init). Also the PHY for port A always gets enabled before we read out the comp value. What are the other port A PHY registers in the above case? Could it be that the port A PHY power gating in PORT_CL1CM_DW28 causes this? Not sure how good it is to reuse the same comp value across multiple off/on cycles, it could change in theory. There could also be some other issue with the port A PHY init. > > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Signed-off-by: Clint Taylor <clinton.a.taylor@xxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_dpio_phy.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dpio_phy.c b/drivers/gpu/drm/i915/intel_dpio_phy.c > index 3c7f10d..7cee57f 100644 > --- a/drivers/gpu/drm/i915/intel_dpio_phy.c > +++ b/drivers/gpu/drm/i915/intel_dpio_phy.c > @@ -422,8 +422,12 @@ static void _bxt_ddi_phy_init(struct drm_i915_private *dev_priv, > * the corresponding calibrated value from PHY1, and disable > * the automatic calibration on PHY0. > */ > - val = dev_priv->bxt_phy_grc = bxt_get_grc(dev_priv, > - phy_info->rcomp_phy); > + if (!dev_priv->bxt_phy_grc) > + val = dev_priv->bxt_phy_grc = bxt_get_grc(dev_priv, > + phy_info->rcomp_phy); > + else > + val = dev_priv->bxt_phy_grc; > + > grc_code = val << GRC_CODE_FAST_SHIFT | > val << GRC_CODE_SLOW_SHIFT | > val; > -- > 1.9.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
