Attachment 86856 Details for Bug 69675 – patch 1/3

[patch] patch 1/3

0001-drm-radeon-use-64-bit-math-to-calculate-CTS-values-f.patch (text/plain), 1.16 KB, created by Alex Deucher on 2013-09-30 15:43:23 UTC

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Creator: Alex Deucher

Created: 2013-09-30 15:43:23 UTC

Size: 1.16 KB

patch

obsolete

>From 6a4a51f43cc6635c7b731d9fb2e1e32333d594fe Mon Sep 17 00:00:00 2001
>From: Alex Deucher <alexander.deucher@amd.com>
>Date: Fri, 27 Sep 2013 18:09:54 -0400
>Subject: [PATCH 1/3] drm/radeon: use 64-bit math to calculate CTS values for
> audio (v2)
>
>Avoid losing precision.  See bug:
>https://bugs.freedesktop.org/show_bug.cgi?id=69675
>
>v2: fix math as per Anssi's comments.
>
>Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>---
> drivers/gpu/drm/radeon/r600_hdmi.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/gpu/drm/radeon/r600_hdmi.c b/drivers/gpu/drm/radeon/r600_hdmi.c
>index b0fa600..49043a5 100644
>--- a/drivers/gpu/drm/radeon/r600_hdmi.c
>+++ b/drivers/gpu/drm/radeon/r600_hdmi.c
>@@ -75,8 +75,15 @@ static const struct radeon_hdmi_acr r600_hdmi_predefined_acr[] = {
>  */
> static void r600_hdmi_calc_cts(uint32_t clock, int *CTS, int N, int freq)
> {
>-	if (*CTS == 0)
>-		*CTS = clock * N / (128 * freq) * 1000;
>+	u64 n;
>+	u32 d;
>+
>+	if (*CTS == 0) {
>+		n = (u64)clock * (u64)N * 1000ULL;
>+		d = 128 * freq;
>+		do_div(n, d);
>+		*CTS = n;
>+	}
> 	DRM_DEBUG("Using ACR timing N=%d CTS=%d for frequency %d\n",
> 		  N, *CTS, freq);
> }
>-- 
>1.8.3.1
>

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Attachments on bug 69675: 86598 | 86739 | 86740 | 86741 | 86856 | 88450 | 88476 | 88775 | 88776

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