diff mbox

drm/i915: add fast boot support for Haswell

Message ID 1375391542-21936-1-git-send-email-furquan@google.com (mailing list archive)
State New, archived
Headers show

Commit Message

Furquan Shaikh Aug. 1, 2013, 9:12 p.m. UTC
Enables getting correct mode clock when reading pipe config

Signed-off-by: Furquan Shaikh <furquan@google.com>
---
 drivers/gpu/drm/i915/intel_ddi.c     | 8 ++++++++
 drivers/gpu/drm/i915/intel_display.c | 9 ++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

Comments

Daniel Vetter Aug. 5, 2013, 7:24 a.m. UTC | #1
On Thu, Aug 01, 2013 at 02:12:22PM -0700, Furquan Shaikh wrote:
> Enables getting correct mode clock when reading pipe config
> 
> Signed-off-by: Furquan Shaikh <furquan@google.com>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c     | 8 ++++++++
>  drivers/gpu/drm/i915/intel_display.c | 9 ++++++++-
>  2 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 931b4bb..fa0af9b 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1269,6 +1269,7 @@ static void intel_ddi_get_config(struct intel_encoder *encoder,
>  	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
>  	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
>  	enum transcoder cpu_transcoder = intel_crtc->config.cpu_transcoder;
> +	int port = intel_ddi_get_encoder_port(encoder);
>  	u32 temp, flags = 0;
>  
>  	temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
> @@ -1282,6 +1283,13 @@ static void intel_ddi_get_config(struct intel_encoder *encoder,
>  		flags |= DRM_MODE_FLAG_NVSYNC;
>  
>  	pipe_config->adjusted_mode.flags |= flags;
> +
> +	if (port == PORT_A) {
> +		if ((I915_READ(DP_A) & DP_PLL_FREQ_MASK) == DP_PLL_FREQ_160MHZ)
> +			pipe_config->port_clock = 162000;
> +		else
> +			pipe_config->port_clock = 270000;
> +	}

I don't think this works correctly since for DP we have new clocks on
haswell, see intel_ddi_pll_mode_set. Also I think it'd be good to go right
ahead and implement clock readout support for all hsw clock sources, not
just DP.
-Daniel

>  }
>  
>  static void intel_ddi_destroy(struct drm_encoder *encoder)
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 3e66f05..681c99a 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7176,6 +7176,8 @@ static void i9xx_crtc_clock_get(struct intel_crtc *crtc,
>  		pipe_config->pixel_multiplier;
>  }
>  
> +#define div_ceil(A, B) ((A)/(B) + ((A)%(B) ? 1 : 0))
> +
>  static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
>  				    struct intel_crtc_config *pipe_config)
>  {
> @@ -7218,7 +7220,11 @@ static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
>  		return;
>  
>  	clock = ((u64)link_m * (u64)link_freq * (u64)repeat);
> -	do_div(clock, link_n);
> +	/* This is required because the value comes out to be in fraction
> +	   (eg. 70699.54). Need to round it up since values are compared in
> +	   drm_mode_equal
> +	*/
> +	clock = div_ceil(clock, link_n);
>  
>  	pipe_config->adjusted_mode.clock = clock;
>  }
> @@ -9588,6 +9594,7 @@ static void intel_init_display(struct drm_device *dev)
>  
>  	if (HAS_DDI(dev)) {
>  		dev_priv->display.get_pipe_config = haswell_get_pipe_config;
> +		dev_priv->display.get_clock = ironlake_crtc_clock_get;
>  		dev_priv->display.crtc_mode_set = haswell_crtc_mode_set;
>  		dev_priv->display.crtc_enable = haswell_crtc_enable;
>  		dev_priv->display.crtc_disable = haswell_crtc_disable;
> -- 
> 1.8.3
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
Furquan Shaikh Aug. 5, 2013, 8:24 p.m. UTC | #2
We tested the submitted patch on several systems here and it seems to be
working fine. So, I'm not sure I understand your comment. Can you please
provide more details?

Thanks,
Furquan


On Mon, Aug 5, 2013 at 12:24 AM, Daniel Vetter <daniel@ffwll.ch> wrote:

> On Thu, Aug 01, 2013 at 02:12:22PM -0700, Furquan Shaikh wrote:
> > Enables getting correct mode clock when reading pipe config
> >
> > Signed-off-by: Furquan Shaikh <furquan@google.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c     | 8 ++++++++
> >  drivers/gpu/drm/i915/intel_display.c | 9 ++++++++-
> >  2 files changed, 16 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c
> b/drivers/gpu/drm/i915/intel_ddi.c
> > index 931b4bb..fa0af9b 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -1269,6 +1269,7 @@ static void intel_ddi_get_config(struct
> intel_encoder *encoder,
> >       struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
> >       struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
> >       enum transcoder cpu_transcoder = intel_crtc->config.cpu_transcoder;
> > +     int port = intel_ddi_get_encoder_port(encoder);
> >       u32 temp, flags = 0;
> >
> >       temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
> > @@ -1282,6 +1283,13 @@ static void intel_ddi_get_config(struct
> intel_encoder *encoder,
> >               flags |= DRM_MODE_FLAG_NVSYNC;
> >
> >       pipe_config->adjusted_mode.flags |= flags;
> > +
> > +     if (port == PORT_A) {
> > +             if ((I915_READ(DP_A) & DP_PLL_FREQ_MASK) ==
> DP_PLL_FREQ_160MHZ)
> > +                     pipe_config->port_clock = 162000;
> > +             else
> > +                     pipe_config->port_clock = 270000;
> > +     }
>
> I don't think this works correctly since for DP we have new clocks on
> haswell, see intel_ddi_pll_mode_set. Also I think it'd be good to go right
> ahead and implement clock readout support for all hsw clock sources, not
> just DP.
> -Daniel
>
> >  }
> >
> >  static void intel_ddi_destroy(struct drm_encoder *encoder)
> > diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> > index 3e66f05..681c99a 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -7176,6 +7176,8 @@ static void i9xx_crtc_clock_get(struct intel_crtc
> *crtc,
> >               pipe_config->pixel_multiplier;
> >  }
> >
> > +#define div_ceil(A, B) ((A)/(B) + ((A)%(B) ? 1 : 0))
> > +
> >  static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
> >                                   struct intel_crtc_config *pipe_config)
> >  {
> > @@ -7218,7 +7220,11 @@ static void ironlake_crtc_clock_get(struct
> intel_crtc *crtc,
> >               return;
> >
> >       clock = ((u64)link_m * (u64)link_freq * (u64)repeat);
> > -     do_div(clock, link_n);
> > +     /* This is required because the value comes out to be in fraction
> > +        (eg. 70699.54). Need to round it up since values are compared in
> > +        drm_mode_equal
> > +     */
> > +     clock = div_ceil(clock, link_n);
> >
> >       pipe_config->adjusted_mode.clock = clock;
> >  }
> > @@ -9588,6 +9594,7 @@ static void intel_init_display(struct drm_device
> *dev)
> >
> >       if (HAS_DDI(dev)) {
> >               dev_priv->display.get_pipe_config =
> haswell_get_pipe_config;
> > +             dev_priv->display.get_clock = ironlake_crtc_clock_get;
> >               dev_priv->display.crtc_mode_set = haswell_crtc_mode_set;
> >               dev_priv->display.crtc_enable = haswell_crtc_enable;
> >               dev_priv->display.crtc_disable = haswell_crtc_disable;
> > --
> > 1.8.3
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
>
Vetter, Daniel Aug. 5, 2013, 8:42 p.m. UTC | #3
On 05/08/2013 22:24, Furquan Shaikh wrote:
> We tested the submitted patch on several systems here and it seems to 
> be working fine. So, I'm not sure I understand your comment. Can you 
> please provide more details?

You check for the bit DP_PLL_FREQ_160MHZ in the register DP_A when 
calculating the reference frequence for port A eDP panels (i.e. the 
assignement of pipe_config->port_clock). This bit is valid on port A for 
ivb, snb & ilk, but not on hsw. Haswell has a complete new way for 
assigning the pll to the port. For solid fastboot support I think we 
need to support them all (i.e. also the hdmi wrpll clocks and while at 
it we might as well write the fdi dotclock readout code, it should be 
almost the same as the DP dotclock computation).
-Daniel
>
> Thanks,
> Furquan
>
>
> On Mon, Aug 5, 2013 at 12:24 AM, Daniel Vetter <daniel@ffwll.ch 
> <mailto:daniel@ffwll.ch>> wrote:
>
>     On Thu, Aug 01, 2013 at 02:12:22PM -0700, Furquan Shaikh wrote:
>     > Enables getting correct mode clock when reading pipe config
>     >
>     > Signed-off-by: Furquan Shaikh <furquan@google.com
>     <mailto:furquan@google.com>>
>     > ---
>     >  drivers/gpu/drm/i915/intel_ddi.c     | 8 ++++++++
>     >  drivers/gpu/drm/i915/intel_display.c | 9 ++++++++-
>     >  2 files changed, 16 insertions(+), 1 deletion(-)
>     >
>     > diff --git a/drivers/gpu/drm/i915/intel_ddi.c
>     b/drivers/gpu/drm/i915/intel_ddi.c
>     > index 931b4bb..fa0af9b 100644
>     > --- a/drivers/gpu/drm/i915/intel_ddi.c
>     > +++ b/drivers/gpu/drm/i915/intel_ddi.c
>     > @@ -1269,6 +1269,7 @@ static void intel_ddi_get_config(struct
>     intel_encoder *encoder,
>     >       struct drm_i915_private *dev_priv =
>     encoder->base.dev->dev_private;
>     >       struct intel_crtc *intel_crtc =
>     to_intel_crtc(encoder->base.crtc);
>     >       enum transcoder cpu_transcoder =
>     intel_crtc->config.cpu_transcoder;
>     > +     int port = intel_ddi_get_encoder_port(encoder);
>     >       u32 temp, flags = 0;
>     >
>     >       temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
>     > @@ -1282,6 +1283,13 @@ static void intel_ddi_get_config(struct
>     intel_encoder *encoder,
>     >               flags |= DRM_MODE_FLAG_NVSYNC;
>     >
>     >       pipe_config->adjusted_mode.flags |= flags;
>     > +
>     > +     if (port == PORT_A) {
>     > +             if ((I915_READ(DP_A) & DP_PLL_FREQ_MASK) ==
>     DP_PLL_FREQ_160MHZ)
>     > +                     pipe_config->port_clock = 162000;
>     > +             else
>     > +                     pipe_config->port_clock = 270000;
>     > +     }
>
>     I don't think this works correctly since for DP we have new clocks on
>     haswell, see intel_ddi_pll_mode_set. Also I think it'd be good to
>     go right
>     ahead and implement clock readout support for all hsw clock
>     sources, not
>     just DP.
>     -Daniel
>
>     >  }
>     >
>     >  static void intel_ddi_destroy(struct drm_encoder *encoder)
>     > diff --git a/drivers/gpu/drm/i915/intel_display.c
>     b/drivers/gpu/drm/i915/intel_display.c
>     > index 3e66f05..681c99a 100644
>     > --- a/drivers/gpu/drm/i915/intel_display.c
>     > +++ b/drivers/gpu/drm/i915/intel_display.c
>     > @@ -7176,6 +7176,8 @@ static void i9xx_crtc_clock_get(struct
>     intel_crtc *crtc,
>     >               pipe_config->pixel_multiplier;
>     >  }
>     >
>     > +#define div_ceil(A, B) ((A)/(B) + ((A)%(B) ? 1 : 0))
>     > +
>     >  static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
>     >                                   struct intel_crtc_config
>     *pipe_config)
>     >  {
>     > @@ -7218,7 +7220,11 @@ static void
>     ironlake_crtc_clock_get(struct intel_crtc *crtc,
>     >               return;
>     >
>     >       clock = ((u64)link_m * (u64)link_freq * (u64)repeat);
>     > -     do_div(clock, link_n);
>     > +     /* This is required because the value comes out to be in
>     fraction
>     > +        (eg. 70699.54). Need to round it up since values are
>     compared in
>     > +        drm_mode_equal
>     > +     */
>     > +     clock = div_ceil(clock, link_n);
>     >
>     >       pipe_config->adjusted_mode.clock = clock;
>     >  }
>     > @@ -9588,6 +9594,7 @@ static void intel_init_display(struct
>     drm_device *dev)
>     >
>     >       if (HAS_DDI(dev)) {
>     > dev_priv->display.get_pipe_config = haswell_get_pipe_config;
>     > +             dev_priv->display.get_clock = ironlake_crtc_clock_get;
>     >               dev_priv->display.crtc_mode_set =
>     haswell_crtc_mode_set;
>     >               dev_priv->display.crtc_enable = haswell_crtc_enable;
>     >               dev_priv->display.crtc_disable = haswell_crtc_disable;
>     > --
>     > 1.8.3
>     >
>     > _______________________________________________
>     > dri-devel mailing list
>     > dri-devel@lists.freedesktop.org
>     <mailto:dri-devel@lists.freedesktop.org>
>     > http://lists.freedesktop.org/mailman/listinfo/dri-devel
>
>     --
>     Daniel Vetter
>     Software Engineer, Intel Corporation
>     +41 (0) 79 365 57 48 <tel:%2B41%20%280%29%2079%20365%2057%2048> -
>     http://blog.ffwll.ch
>
>

Intel Semiconductor AG
Registered No. 020.30.913.786-7
Registered Office: World Trade Center, Leutschenbachstrasse 95, 8050 Zurich, Switzerland

This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.
Daniel Vetter Aug. 5, 2013, 8:45 p.m. UTC | #4
[Now without the confidential header which shouldn't have spilled to
public lists, please reply to this one here.]

On Mon, Aug 05, 2013 at 01:24:15PM -0700, Furquan Shaikh wrote:
> We tested the submitted patch on several systems here and it seems to be
> working fine. So, I'm not sure I understand your comment. Can you please
> provide more details?

You check for the bit DP_PLL_FREQ_160MHZ in the register DP_A when
calculating the reference frequence for port A eDP panels (i.e. the
assignement of pipe_config->port_clock). This bit is valid on port A
for ivb, snb & ilk, but not on hsw. Haswell has a complete new way for
assigning the pll to the port. For solid fastboot support I think we
need to support them all (i.e. also the hdmi wrpll clocks and while at
it we might as well write the fdi dotclock readout code, it should be
almost the same as the DP dotclock computation).
-Daniel

> 
> Thanks,
> Furquan
> 
> 
> On Mon, Aug 5, 2013 at 12:24 AM, Daniel Vetter <daniel@ffwll.ch> wrote:
> 
> > On Thu, Aug 01, 2013 at 02:12:22PM -0700, Furquan Shaikh wrote:
> > > Enables getting correct mode clock when reading pipe config
> > >
> > > Signed-off-by: Furquan Shaikh <furquan@google.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_ddi.c     | 8 ++++++++
> > >  drivers/gpu/drm/i915/intel_display.c | 9 ++++++++-
> > >  2 files changed, 16 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/intel_ddi.c
> > b/drivers/gpu/drm/i915/intel_ddi.c
> > > index 931b4bb..fa0af9b 100644
> > > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > > @@ -1269,6 +1269,7 @@ static void intel_ddi_get_config(struct
> > intel_encoder *encoder,
> > >       struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
> > >       struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
> > >       enum transcoder cpu_transcoder = intel_crtc->config.cpu_transcoder;
> > > +     int port = intel_ddi_get_encoder_port(encoder);
> > >       u32 temp, flags = 0;
> > >
> > >       temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
> > > @@ -1282,6 +1283,13 @@ static void intel_ddi_get_config(struct
> > intel_encoder *encoder,
> > >               flags |= DRM_MODE_FLAG_NVSYNC;
> > >
> > >       pipe_config->adjusted_mode.flags |= flags;
> > > +
> > > +     if (port == PORT_A) {
> > > +             if ((I915_READ(DP_A) & DP_PLL_FREQ_MASK) ==
> > DP_PLL_FREQ_160MHZ)
> > > +                     pipe_config->port_clock = 162000;
> > > +             else
> > > +                     pipe_config->port_clock = 270000;
> > > +     }
> >
> > I don't think this works correctly since for DP we have new clocks on
> > haswell, see intel_ddi_pll_mode_set. Also I think it'd be good to go right
> > ahead and implement clock readout support for all hsw clock sources, not
> > just DP.
> > -Daniel
> >
> > >  }
> > >
> > >  static void intel_ddi_destroy(struct drm_encoder *encoder)
> > > diff --git a/drivers/gpu/drm/i915/intel_display.c
> > b/drivers/gpu/drm/i915/intel_display.c
> > > index 3e66f05..681c99a 100644
> > > --- a/drivers/gpu/drm/i915/intel_display.c
> > > +++ b/drivers/gpu/drm/i915/intel_display.c
> > > @@ -7176,6 +7176,8 @@ static void i9xx_crtc_clock_get(struct intel_crtc
> > *crtc,
> > >               pipe_config->pixel_multiplier;
> > >  }
> > >
> > > +#define div_ceil(A, B) ((A)/(B) + ((A)%(B) ? 1 : 0))
> > > +
> > >  static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
> > >                                   struct intel_crtc_config *pipe_config)
> > >  {
> > > @@ -7218,7 +7220,11 @@ static void ironlake_crtc_clock_get(struct
> > intel_crtc *crtc,
> > >               return;
> > >
> > >       clock = ((u64)link_m * (u64)link_freq * (u64)repeat);
> > > -     do_div(clock, link_n);
> > > +     /* This is required because the value comes out to be in fraction
> > > +        (eg. 70699.54). Need to round it up since values are compared in
> > > +        drm_mode_equal
> > > +     */
> > > +     clock = div_ceil(clock, link_n);
> > >
> > >       pipe_config->adjusted_mode.clock = clock;
> > >  }
> > > @@ -9588,6 +9594,7 @@ static void intel_init_display(struct drm_device
> > *dev)
> > >
> > >       if (HAS_DDI(dev)) {
> > >               dev_priv->display.get_pipe_config =
> > haswell_get_pipe_config;
> > > +             dev_priv->display.get_clock = ironlake_crtc_clock_get;
> > >               dev_priv->display.crtc_mode_set = haswell_crtc_mode_set;
> > >               dev_priv->display.crtc_enable = haswell_crtc_enable;
> > >               dev_priv->display.crtc_disable = haswell_crtc_disable;
> > > --
> > > 1.8.3
> > >
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel@lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/dri-devel
> >
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
> >

> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
Jesse Barnes Aug. 5, 2013, 10:42 p.m. UTC | #5
On Thu,  1 Aug 2013 14:12:22 -0700
Furquan Shaikh <furquan@google.com> wrote:

> @@ -1282,6 +1283,13 @@ static void intel_ddi_get_config(struct intel_encoder *encoder,
>  		flags |= DRM_MODE_FLAG_NVSYNC;
>  
>  	pipe_config->adjusted_mode.flags |= flags;
> +
> +	if (port == PORT_A) {
> +		if ((I915_READ(DP_A) & DP_PLL_FREQ_MASK) == DP_PLL_FREQ_160MHZ)
> +			pipe_config->port_clock = 162000;
> +		else
> +			pipe_config->port_clock = 270000;
> +	}

Sorry Furquan, I should have checked this earlier, I knew it was too
good to be true. :)

On HSW, DP_A is actually DDI_BUF_CTL, and it has a different layout
than the old DP_A reg.  Like Daniel said, doing it the old way is
invalid on HSW.  It might work in your configs, but I think that's just
coincidence, since bit 16 is the port reversal bit on HSW, not the
clock freq.

To get the clock freq, you need to look at 0x45020 to find the refclk,
then look at the WRPLL_CTL for the pipe to get the dividers.  That's
what Daniel meant when he asked for a full "clock_get" function.  It's
only a little more complicated, but you'll need docs for it.  Charlie
Huang ought to be able to get you the NDA docs that should have the
info you need.

Thanks,
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 931b4bb..fa0af9b 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1269,6 +1269,7 @@  static void intel_ddi_get_config(struct intel_encoder *encoder,
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
 	enum transcoder cpu_transcoder = intel_crtc->config.cpu_transcoder;
+	int port = intel_ddi_get_encoder_port(encoder);
 	u32 temp, flags = 0;
 
 	temp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
@@ -1282,6 +1283,13 @@  static void intel_ddi_get_config(struct intel_encoder *encoder,
 		flags |= DRM_MODE_FLAG_NVSYNC;
 
 	pipe_config->adjusted_mode.flags |= flags;
+
+	if (port == PORT_A) {
+		if ((I915_READ(DP_A) & DP_PLL_FREQ_MASK) == DP_PLL_FREQ_160MHZ)
+			pipe_config->port_clock = 162000;
+		else
+			pipe_config->port_clock = 270000;
+	}
 }
 
 static void intel_ddi_destroy(struct drm_encoder *encoder)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3e66f05..681c99a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7176,6 +7176,8 @@  static void i9xx_crtc_clock_get(struct intel_crtc *crtc,
 		pipe_config->pixel_multiplier;
 }
 
+#define div_ceil(A, B) ((A)/(B) + ((A)%(B) ? 1 : 0))
+
 static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
 				    struct intel_crtc_config *pipe_config)
 {
@@ -7218,7 +7220,11 @@  static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
 		return;
 
 	clock = ((u64)link_m * (u64)link_freq * (u64)repeat);
-	do_div(clock, link_n);
+	/* This is required because the value comes out to be in fraction
+	   (eg. 70699.54). Need to round it up since values are compared in
+	   drm_mode_equal
+	*/
+	clock = div_ceil(clock, link_n);
 
 	pipe_config->adjusted_mode.clock = clock;
 }
@@ -9588,6 +9594,7 @@  static void intel_init_display(struct drm_device *dev)
 
 	if (HAS_DDI(dev)) {
 		dev_priv->display.get_pipe_config = haswell_get_pipe_config;
+		dev_priv->display.get_clock = ironlake_crtc_clock_get;
 		dev_priv->display.crtc_mode_set = haswell_crtc_mode_set;
 		dev_priv->display.crtc_enable = haswell_crtc_enable;
 		dev_priv->display.crtc_disable = haswell_crtc_disable;