From 3194ed497939c6448005542e3ca4fa2386968fa0 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Thu, 21 Apr 2016 17:49:11 +0200 Subject: ALSA: hda - Fix possible race on regmap bypass flip HD-audio driver uses regmap cache bypass feature for reading a raw value without the cache. But this is racy since both the cached and the uncached reads may occur concurrently. The former is done via the normal control API access while the latter comes from the proc file read. Even though the regmap itself has the protection against the concurrent accesses, the flag set/reset is done without the protection, so it may lead to inconsistent state of bypass flag that doesn't match with the current read and occasionally result in a kernel WARNING like: WARNING: CPU: 3 PID: 2731 at drivers/base/regmap/regcache.c:499 regcache_cache_only+0x78/0x93 One way to work around such a problem is to wrap with a mutex. But in this case, the solution is simpler: for the uncached read, we just skip the regmap and directly calls its accessor. The verb execution there is protected by itself, so basically it's safe to call individually. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=116171 Signed-off-by: Takashi Iwai --- sound/hda/hdac_device.c | 10 ++++------ sound/hda/hdac_regmap.c | 40 ++++++++++++++++++++++++++++------------ 2 files changed, 32 insertions(+), 18 deletions(-) (limited to 'sound/hda') diff --git a/sound/hda/hdac_device.c b/sound/hda/hdac_device.c index d1a4d6973330..03c9872c31cf 100644 --- a/sound/hda/hdac_device.c +++ b/sound/hda/hdac_device.c @@ -299,13 +299,11 @@ EXPORT_SYMBOL_GPL(_snd_hdac_read_parm); int snd_hdac_read_parm_uncached(struct hdac_device *codec, hda_nid_t nid, int parm) { - int val; + unsigned int cmd, val; - if (codec->regmap) - regcache_cache_bypass(codec->regmap, true); - val = snd_hdac_read_parm(codec, nid, parm); - if (codec->regmap) - regcache_cache_bypass(codec->regmap, false); + cmd = snd_hdac_regmap_encode_verb(nid, AC_VERB_PARAMETERS) | parm; + if (snd_hdac_regmap_read_raw_uncached(codec, cmd, &val) < 0) + return -1; return val; } EXPORT_SYMBOL_GPL(snd_hdac_read_parm_uncached); diff --git a/sound/hda/hdac_regmap.c b/sound/hda/hdac_regmap.c index bdbcd6b75ff6..87041ddd29cb 100644 --- a/sound/hda/hdac_regmap.c +++ b/sound/hda/hdac_regmap.c @@ -453,14 +453,30 @@ int snd_hdac_regmap_write_raw(struct hdac_device *codec, unsigned int reg, EXPORT_SYMBOL_GPL(snd_hdac_regmap_write_raw); static int reg_raw_read(struct hdac_device *codec, unsigned int reg, - unsigned int *val) + unsigned int *val, bool uncached) { - if (!codec->regmap) + if (uncached || !codec->regmap) return hda_reg_read(codec, reg, val); else return regmap_read(codec->regmap, reg, val); } +static int __snd_hdac_regmap_read_raw(struct hdac_device *codec, + unsigned int reg, unsigned int *val, + bool uncached) +{ + int err; + + err = reg_raw_read(codec, reg, val, uncached); + if (err == -EAGAIN) { + err = snd_hdac_power_up_pm(codec); + if (!err) + err = reg_raw_read(codec, reg, val, uncached); + snd_hdac_power_down_pm(codec); + } + return err; +} + /** * snd_hdac_regmap_read_raw - read a pseudo register with power mgmt * @codec: the codec object @@ -472,19 +488,19 @@ static int reg_raw_read(struct hdac_device *codec, unsigned int reg, int snd_hdac_regmap_read_raw(struct hdac_device *codec, unsigned int reg, unsigned int *val) { - int err; - - err = reg_raw_read(codec, reg, val); - if (err == -EAGAIN) { - err = snd_hdac_power_up_pm(codec); - if (!err) - err = reg_raw_read(codec, reg, val); - snd_hdac_power_down_pm(codec); - } - return err; + return __snd_hdac_regmap_read_raw(codec, reg, val, false); } EXPORT_SYMBOL_GPL(snd_hdac_regmap_read_raw); +/* Works like snd_hdac_regmap_read_raw(), but this doesn't read from the + * cache but always via hda verbs. + */ +int snd_hdac_regmap_read_raw_uncached(struct hdac_device *codec, + unsigned int reg, unsigned int *val) +{ + return __snd_hdac_regmap_read_raw(codec, reg, val, true); +} + /** * snd_hdac_regmap_update_raw - update a pseudo register with power mgmt * @codec: the codec object -- cgit From bb03ed216370cb021f377f923471e56d1de3ff5d Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Thu, 21 Apr 2016 16:39:17 +0200 Subject: ALSA: hda - Update BCLK also at hotplug for i915 HSW/BDW The recent bug report suggests that BCLK setup for i915 HSW/BDW needs to be updated at each HDMI hotplug, not only at initialization and resume. That is, we need to update HSW_EM4 and HSW_EM5 registers at ELD notification, too. Otherwise the HDMI audio may be out of sync and played in a wrong pitch. However, the HDA codec driver has no access to the controller registers, and currently the code managing these registers is in hda_intel.c, i.e. local to the controller driver. For allowing the explicit BCLK update from the codec driver, as in this patch, the former haswell_set_bclk() in hda_intel.c is moved to hdac_i915.c and exposed as snd_hdac_i915_set_bclk(). This is called from both the HDA controller driver and intel_pin_eld_notify() in HDMI codec driver. Along with this change, snd_hdac_get_display_clk() gets dropped as it's no longer used. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91410 Cc: # v4.5+ Signed-off-by: Takashi Iwai --- sound/hda/hdac_i915.c | 62 ++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 51 insertions(+), 11 deletions(-) (limited to 'sound/hda') diff --git a/sound/hda/hdac_i915.c b/sound/hda/hdac_i915.c index 54babe1c0b16..607bbeaebddf 100644 --- a/sound/hda/hdac_i915.c +++ b/sound/hda/hdac_i915.c @@ -20,6 +20,7 @@ #include #include #include +#include static struct i915_audio_component *hdac_acomp; @@ -97,26 +98,65 @@ int snd_hdac_display_power(struct hdac_bus *bus, bool enable) } EXPORT_SYMBOL_GPL(snd_hdac_display_power); +#define CONTROLLER_IN_GPU(pci) (((pci)->device == 0x0a0c) || \ + ((pci)->device == 0x0c0c) || \ + ((pci)->device == 0x0d0c) || \ + ((pci)->device == 0x160c)) + /** - * snd_hdac_get_display_clk - Get CDCLK in kHz + * snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW * @bus: HDA core bus * - * This function is supposed to be used only by a HD-audio controller - * driver that needs the interaction with i915 graphics. + * Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK + * depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value) + * are used to convert CDClk (Core Display Clock) to 24MHz BCLK: + * BCLK = CDCLK * M / N + * The values will be lost when the display power well is disabled and need to + * be restored to avoid abnormal playback speed. * - * This function queries CDCLK value in kHz from the graphics driver and - * returns the value. A negative code is returned in error. + * Call this function at initializing and changing power well, as well as + * at ELD notifier for the hotplug. */ -int snd_hdac_get_display_clk(struct hdac_bus *bus) +void snd_hdac_i915_set_bclk(struct hdac_bus *bus) { struct i915_audio_component *acomp = bus->audio_component; + struct pci_dev *pci = to_pci_dev(bus->dev); + int cdclk_freq; + unsigned int bclk_m, bclk_n; + + if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq) + return; /* only for i915 binding */ + if (!CONTROLLER_IN_GPU(pci)) + return; /* only HSW/BDW */ + + cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev); + switch (cdclk_freq) { + case 337500: + bclk_m = 16; + bclk_n = 225; + break; + + case 450000: + default: /* default CDCLK 450MHz */ + bclk_m = 4; + bclk_n = 75; + break; + + case 540000: + bclk_m = 4; + bclk_n = 90; + break; + + case 675000: + bclk_m = 8; + bclk_n = 225; + break; + } - if (!acomp || !acomp->ops) - return -ENODEV; - - return acomp->ops->get_cdclk_freq(acomp->dev); + snd_hdac_chip_writew(bus, HSW_EM4, bclk_m); + snd_hdac_chip_writew(bus, HSW_EM5, bclk_n); } -EXPORT_SYMBOL_GPL(snd_hdac_get_display_clk); +EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk); /* There is a fixed mapping between audio pin node and display port * on current Intel platforms: -- cgit