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Commit 062c2e43 authored by Alex Deucher's avatar Alex Deucher
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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: default avatarAlex Deucher <alexander.deucher@amd.com>
parent aaed41ec

drivers/gpu/drm/radeon/r600_hdmi.c

+9 −2
Original line number Diff line number Diff line
@@ -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);

}