From: Jani Nikula <jani.nikula@linux.intel.com>
To: ville.syrjala@linux.intel.com, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 1/8] drm/i915: Don't factor in pixel multplier when deriving dotclock from link clock and M/N values
Date: Wed, 04 Sep 2013 16:22:19 +0300 [thread overview]
Message-ID: <87eh94iuwk.fsf@intel.com> (raw)
In-Reply-To: <1378293292-30682-2-git-send-email-ville.syrjala@linux.intel.com>
On Wed, 04 Sep 2013, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> We feed the non-multiplied clock to intel_link_compute_m_n(), so the
> opposite operation should use the same order of operations. So we just
> multiply by pixel_multiplier in the end now.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> drivers/gpu/drm/i915/intel_display.c | 15 +++++++--------
> 1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index d88057e..b45c6e6 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7340,20 +7340,18 @@ static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
> struct drm_device *dev = crtc->base.dev;
> struct drm_i915_private *dev_priv = dev->dev_private;
> enum transcoder cpu_transcoder = pipe_config->cpu_transcoder;
> - int link_freq, repeat;
> + int link_freq;
> u64 clock;
> u32 link_m, link_n;
>
> - repeat = pipe_config->pixel_multiplier;
> -
> /*
> * The calculation for the data clock is:
> - * pixel_clock = ((m/n)*(link_clock * nr_lanes * repeat))/bpp
> + * pixel_clock = ((m/n)*(link_clock * nr_lanes))/bpp
> * But we want to avoid losing precison if possible, so:
> - * pixel_clock = ((m * link_clock * nr_lanes * repeat)/(n*bpp))
> + * pixel_clock = ((m * link_clock * nr_lanes)/(n*bpp))
> *
> * and the link clock is simpler:
> - * link_clock = (m * link_clock * repeat) / n
> + * link_clock = (m * link_clock) / n
> */
>
> /*
> @@ -7375,10 +7373,11 @@ static void ironlake_crtc_clock_get(struct intel_crtc *crtc,
> if (!link_m || !link_n)
> return;
>
> - clock = ((u64)link_m * (u64)link_freq * (u64)repeat);
> + clock = ((u64)link_m * (u64)link_freq);
> do_div(clock, link_n);
>
> - pipe_config->adjusted_mode.clock = clock;
> + pipe_config->adjusted_mode.clock = clock *
> + pipe_config->pixel_multiplier;
> }
>
> /** Returns the currently programmed mode of the given pipe. */
> --
> 1.8.1.5
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
--
Jani Nikula, Intel Open Source Technology Center
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2013-09-04 13:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-04 11:14 [PATCH 0/8] drm/i915: adjusted_mode.clock vs. port_clock v2 ville.syrjala
2013-09-04 11:14 ` [PATCH 1/8] drm/i915: Don't factor in pixel multplier when deriving dotclock from link clock and M/N values ville.syrjala
2013-09-04 13:22 ` Jani Nikula [this message]
2013-09-04 11:14 ` [PATCH 2/8] drm/i915: Make adjusted_mode.clock non-pixel multiplied ville.syrjala
2013-09-04 11:14 ` [PATCH 3/8] drm/i915: Add support for pipe_bpp readout ville.syrjala
2013-09-06 13:18 ` [PATCH v2] " ville.syrjala
2013-09-04 11:14 ` [PATCH 4/8] drm/i915: Move i9xx_crtc_clock_get() and ironlake_crtc_clock_get() earlier ville.syrjala
2013-09-04 13:22 ` Jani Nikula
2013-09-04 11:14 ` [PATCH 5/8] drm/i915: Fix port_clock readout for SDVO and HDMI 12bpc cases ville.syrjala
2013-09-06 13:24 ` [PATCH] drm/i915: Fix issues caused from get_clock elimination ville.syrjala
2013-09-06 16:00 ` Daniel Vetter
2013-09-04 11:14 ` [PATCH 6/8] drm/i915: Make intel_fuzzy_clock_check() take in arbitrary clocks ville.syrjala
2013-09-04 11:14 ` [PATCH v2 7/8] drm/i915: Add PIPE_CONF_CHECK_CLOCK_FUZZY() ville.syrjala
2013-09-04 11:14 ` [PATCH v2 8/8] drm/i915: Add fuzzy clock check for port_clock ville.syrjala
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