Attachment 78330 Details for Bug 49402 – Possible fix

[patch] Possible fix

0001-drm-i915-Make-data-link-N-value-power-of-two.patch (text/plain), 2.04 KB, created by Ville Syrjala on 2013-04-22 14:27:28 UTC

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Creator: Ville Syrjala

Created: 2013-04-22 14:27:28 UTC

Size: 2.04 KB

patch

obsolete

>From 9db22dae0e388c73516169ea5444145d68288120 Mon Sep 17 00:00:00 2001
>From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
>Date: Mon, 22 Apr 2013 17:01:14 +0300
>Subject: [RFC][PATCH] drm/i915: Make data/link N value power of two
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>The BIOS uses power of two values for the data/link N value.
>
>Follow suit to make the Zotac DP to dual-HDMI dongle work.
>
>Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49402
>Signed-off-by: Ville SyrjÃ¤lÃ¤ <ville.syrjala@linux.intel.com>
>---
>Warning: I've only tested this with the Zotac dongle hooked to my 1080p
>Samsumg telly. Whether or not it works with other displays is an open
>question.
>
> drivers/gpu/drm/i915/intel_display.c | 23 +++++++++++++++++------
> 1 file changed, 17 insertions(+), 6 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>index 74156e2..fea9c99 100644
>--- a/drivers/gpu/drm/i915/intel_display.c
>+++ b/drivers/gpu/drm/i915/intel_display.c
>@@ -4151,18 +4151,29 @@ intel_reduce_ratio(uint32_t *num, uint32_t *den)
> 	}
> }
> 
>+static void compute_m_n(int m, int n, uint32_t *ret_m, uint32_t *ret_n)
>+{
>+	if (n >= 1 << 23)
>+		*ret_n = 1 << 23;
>+	else
>+		*ret_n = roundup_pow_of_two(n);
>+	*ret_m = div_u64((uint64_t) m * *ret_n, n);
>+	intel_reduce_ratio(ret_m, ret_n);
>+}
>+
> void
> intel_link_compute_m_n(int bits_per_pixel, int nlanes,
> 		       int pixel_clock, int link_clock,
> 		       struct intel_link_m_n *m_n)
> {
> 	m_n->tu = 64;
>-	m_n->gmch_m = bits_per_pixel * pixel_clock;
>-	m_n->gmch_n = link_clock * nlanes * 8;
>-	intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
>-	m_n->link_m = pixel_clock;
>-	m_n->link_n = link_clock;
>-	intel_reduce_ratio(&m_n->link_m, &m_n->link_n);
>+
>+	compute_m_n(bits_per_pixel * pixel_clock,
>+		    link_clock * nlanes * 8,
>+		    &m_n->gmch_m, &m_n->gmch_n);
>+
>+	compute_m_n(pixel_clock, link_clock,
>+		    &m_n->link_m, &m_n->link_n);
> }
> 
> static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv)
>-- 
>1.8.1.5
>

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Attachments on bug 49402: 60931 | 60932 | 60933 | 60937 | 60938 | 60939 | 78330 | 86402 | 86720

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