[Intel-gfx] [PATCH] drm/i915: Preserve the DDI_A_4_LANES bit from the bios

[Daniel Vetter]

On Fri, Jul 12, 2013 at 07:50:31PM -0300, Paulo Zanoni wrote:
> 2013/7/12 Paulo Zanoni <przanoni at gmail.com>:
> > 2013/7/12 Stéphane Marchesin <marcheu at chromium.org>:
> >> Otherwise the DDI_A_4_LANES bit gets lost and we can't use > 2 lanes
> >> on eDP. This fixes eDP on hsw with > 2 lanes.
> >>
> >> Also s/port_reversal/saved_port_bits/ since the current name is
> >> confusing.
> >>
> >> Signed-off-by: Stéphane Marchesin <marcheu at chromium.org>

Picked up for -fixes, thanks for the patch.

> >
> > Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> >
> > Should we also Cc: stable at kernel.org ?

Done.

> 
> And I forgot to mention: as discussed on IRC, we need 2 additional
> patches on top of that:
> - Don't intel_init_crt if DDI A has 4 lanes
> - We should do our own wrapper around drm_dp_max_lane_count and return
> minimum of drm_dp_max_lane_count and the value set on DDI_BUF_CTL_A

Yeah. We have a similar issue with dp link speeds past 2.7 Ghz (and maybe
also the in-between special link clocks for eDP) where we need to apply
platform/port specific limits on top of the sink limits. I'd say we should
add those parameters to our dp structure so that the init code can fill it
out.
-Daniel

> 
> >
> >> ---
> >>  drivers/gpu/drm/i915/intel_ddi.c | 10 ++++++----
> >>  drivers/gpu/drm/i915/intel_drv.h |  2 +-
> >>  2 files changed, 7 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> >> index 324211a..b042ee5 100644
> >> --- a/drivers/gpu/drm/i915/intel_ddi.c
> >> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> >> @@ -301,7 +301,7 @@ static void intel_ddi_mode_set(struct drm_encoder *encoder,
> >>                 struct intel_digital_port *intel_dig_port =
> >>                         enc_to_dig_port(encoder);
> >>
> >> -               intel_dp->DP = intel_dig_port->port_reversal |
> >> +               intel_dp->DP = intel_dig_port->saved_port_bits |
> >>                                DDI_BUF_CTL_ENABLE | DDI_BUF_EMP_400MV_0DB_HSW;
> >>                 intel_dp->DP |= DDI_PORT_WIDTH(intel_dp->lane_count);
> >>
> >> @@ -1109,7 +1109,8 @@ static void intel_enable_ddi(struct intel_encoder *intel_encoder)
> >>                  * enabling the port.
> >>                  */
> >>                 I915_WRITE(DDI_BUF_CTL(port),
> >> -                          intel_dig_port->port_reversal | DDI_BUF_CTL_ENABLE);
> >> +                          intel_dig_port->saved_port_bits |
> >> +                          DDI_BUF_CTL_ENABLE);
> >>         } else if (type == INTEL_OUTPUT_EDP) {
> >>                 struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> >>
> >> @@ -1347,8 +1348,9 @@ void intel_ddi_init(struct drm_device *dev, enum port port)
> >>         intel_encoder->get_config = intel_ddi_get_config;
> >>
> >>         intel_dig_port->port = port;
> >> -       intel_dig_port->port_reversal = I915_READ(DDI_BUF_CTL(port)) &
> >> -                                       DDI_BUF_PORT_REVERSAL;
> >> +       intel_dig_port->saved_port_bits = I915_READ(DDI_BUF_CTL(port)) &
> >> +                                         (DDI_BUF_PORT_REVERSAL |
> >> +                                          DDI_A_4_LANES);
> >>         intel_dig_port->dp.output_reg = DDI_BUF_CTL(port);
> >>
> >>         intel_encoder->type = INTEL_OUTPUT_UNKNOWN;
> >> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> >> index c8c9b6f..b7d6e09 100644
> >> --- a/drivers/gpu/drm/i915/intel_drv.h
> >> +++ b/drivers/gpu/drm/i915/intel_drv.h
> >> @@ -504,7 +504,7 @@ struct intel_dp {
> >>  struct intel_digital_port {
> >>         struct intel_encoder base;
> >>         enum port port;
> >> -       u32 port_reversal;
> >> +       u32 saved_port_bits;
> >>         struct intel_dp dp;
> >>         struct intel_hdmi hdmi;
> >>  };
> >> --
> >> 1.8.3
> >>
> >> _______________________________________________
> >> Intel-gfx mailing list
> >> Intel-gfx at lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> >
> >
> > --
> > Paulo Zanoni
> 
> 
> 
> -- 
> Paulo Zanoni
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch