Bugzilla: 1010679 Upstream-status: 3.13 From 908171aa738b5bbcc6241cec46f73fcd57dd00d4 Mon Sep 17 00:00:00 2001 From: Pierre Ossman Date: Wed, 6 Nov 2013 20:00:32 +0100 Subject: [PATCH 1/2] drm/radeon/audio: correct ACR table The values were taken from the HDMI spec, but they assumed exact x/1.001 clocks. Since we round the clocks, we also need to calculate different N and CTS values. Note that the N for 25.2/1.001 MHz at 44.1 kHz audio is out of spec. Hopefully this mode is rarely used and/or HDMI sinks tolerate overly large values of N. bug: https://bugs.freedesktop.org/show_bug.cgi?id=69675 Signed-off-by: Pierre Ossman Signed-off-by: Alex Deucher --- drivers/gpu/drm/radeon/r600_hdmi.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/radeon/r600_hdmi.c b/drivers/gpu/drm/radeon/r600_hdmi.c index 4140fe8..e8ca095 100644 --- a/drivers/gpu/drm/radeon/r600_hdmi.c +++ b/drivers/gpu/drm/radeon/r600_hdmi.c @@ -57,15 +57,15 @@ enum r600_hdmi_iec_status_bits { static const struct radeon_hdmi_acr r600_hdmi_predefined_acr[] = { /* 32kHz 44.1kHz 48kHz */ /* Clock N CTS N CTS N CTS */ - { 25175, 4576, 28125, 7007, 31250, 6864, 28125 }, /* 25,20/1.001 MHz */ + { 25175, 4096, 25175, 28224, 125875, 6144, 25175 }, /* 25,20/1.001 MHz */ { 25200, 4096, 25200, 6272, 28000, 6144, 25200 }, /* 25.20 MHz */ { 27000, 4096, 27000, 6272, 30000, 6144, 27000 }, /* 27.00 MHz */ { 27027, 4096, 27027, 6272, 30030, 6144, 27027 }, /* 27.00*1.001 MHz */ { 54000, 4096, 54000, 6272, 60000, 6144, 54000 }, /* 54.00 MHz */ { 54054, 4096, 54054, 6272, 60060, 6144, 54054 }, /* 54.00*1.001 MHz */ - { 74176, 11648, 210937, 17836, 234375, 11648, 140625 }, /* 74.25/1.001 MHz */ + { 74176, 4096, 74176, 5733, 75335, 6144, 74176 }, /* 74.25/1.001 MHz */ { 74250, 4096, 74250, 6272, 82500, 6144, 74250 }, /* 74.25 MHz */ - { 148352, 11648, 421875, 8918, 234375, 5824, 140625 }, /* 148.50/1.001 MHz */ + { 148352, 4096, 148352, 5733, 150670, 6144, 148352 }, /* 148.50/1.001 MHz */ { 148500, 4096, 148500, 6272, 165000, 6144, 148500 }, /* 148.50 MHz */ { 0, 4096, 0, 6272, 0, 6144, 0 } /* Other */ }; -- 1.8.3.1 From 05e4776357fe7217e531cbaaa163e24f688d10ce Mon Sep 17 00:00:00 2001 From: Pierre Ossman Date: Wed, 6 Nov 2013 20:09:08 +0100 Subject: [PATCH 2/2] drm/radeon/audio: improve ACR calculation In order to have any realistic chance of calculating proper ACR values, we need to be able to calculate both N and CTS, not just CTS. We still aim for the ideal N as specified in the HDMI spec though. bug: https://bugs.freedesktop.org/show_bug.cgi?id=69675 Signed-off-by: Pierre Ossman Signed-off-by: Alex Deucher --- drivers/gpu/drm/radeon/r600_hdmi.c | 68 ++++++++++++++++++++++++++------------ 1 file changed, 46 insertions(+), 22 deletions(-) diff --git a/drivers/gpu/drm/radeon/r600_hdmi.c b/drivers/gpu/drm/radeon/r600_hdmi.c index e8ca095..92c6df7 100644 --- a/drivers/gpu/drm/radeon/r600_hdmi.c +++ b/drivers/gpu/drm/radeon/r600_hdmi.c @@ -24,6 +24,7 @@ * Authors: Christian König */ #include +#include #include #include #include "radeon.h" @@ -67,25 +68,47 @@ static const struct radeon_hdmi_acr r600_hdmi_predefined_acr[] = { { 74250, 4096, 74250, 6272, 82500, 6144, 74250 }, /* 74.25 MHz */ { 148352, 4096, 148352, 5733, 150670, 6144, 148352 }, /* 148.50/1.001 MHz */ { 148500, 4096, 148500, 6272, 165000, 6144, 148500 }, /* 148.50 MHz */ - { 0, 4096, 0, 6272, 0, 6144, 0 } /* Other */ }; + /* - * calculate CTS value if it's not found in the table + * calculate CTS and N values if they are not found in the table */ -static void r600_hdmi_calc_cts(uint32_t clock, int *CTS, int N, int freq) +static void r600_hdmi_calc_cts(uint32_t clock, int *CTS, int *N, int freq) { - 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); + int n, cts; + unsigned long div, mul; + + /* Safe, but overly large values */ + n = 128 * freq; + cts = clock * 1000; + + /* Smallest valid fraction */ + div = gcd(n, cts); + + n /= div; + cts /= div; + + /* + * The optimal N is 128*freq/1000. Calculate the closest larger + * value that doesn't truncate any bits. + */ + mul = ((128*freq/1000) + (n-1))/n; + + n *= mul; + cts *= mul; + + /* Check that we are in spec (not always possible) */ + if (n < (128*freq/1500)) + printk(KERN_WARNING "Calculated ACR N value is too small. You may experience audio problems.\n"); + if (n > (128*freq/300)) + printk(KERN_WARNING "Calculated ACR N value is too large. You may experience audio problems.\n"); + + *N = n; + *CTS = cts; + + DRM_DEBUG("Calculated ACR timing N=%d CTS=%d for frequency %d\n", + *N, *CTS, freq); } struct radeon_hdmi_acr r600_hdmi_acr(uint32_t clock) @@ -93,15 +116,16 @@ struct radeon_hdmi_acr r600_hdmi_acr(uint32_t clock) struct radeon_hdmi_acr res; u8 i; - for (i = 0; r600_hdmi_predefined_acr[i].clock != clock && - r600_hdmi_predefined_acr[i].clock != 0; i++) - ; - res = r600_hdmi_predefined_acr[i]; + /* Precalculated values for common clocks */ + for (i = 0; i < ARRAY_SIZE(r600_hdmi_predefined_acr); i++) { + if (r600_hdmi_predefined_acr[i].clock == clock) + return r600_hdmi_predefined_acr[i]; + } - /* In case some CTS are missing */ - r600_hdmi_calc_cts(clock, &res.cts_32khz, res.n_32khz, 32000); - r600_hdmi_calc_cts(clock, &res.cts_44_1khz, res.n_44_1khz, 44100); - r600_hdmi_calc_cts(clock, &res.cts_48khz, res.n_48khz, 48000); + /* And odd clocks get manually calculated */ + r600_hdmi_calc_cts(clock, &res.cts_32khz, &res.n_32khz, 32000); + r600_hdmi_calc_cts(clock, &res.cts_44_1khz, &res.n_44_1khz, 44100); + r600_hdmi_calc_cts(clock, &res.cts_48khz, &res.n_48khz, 48000); return res; } -- 1.8.3.1