linux-stable/sound/hda/hdac_i915.c
Samuel Thibault 74bf71ed79 ALSA: hda: Fix 1-minute detection delay when i915 module is not available
Distribution installation images such as Debian include different sets
of modules which can be downloaded dynamically.  Such images may notably
include the hda sound modules but not the i915 DRM module, even if the
latter was enabled at build time, as reported on
https://bugs.debian.org/931507

In such a case hdac_i915 would be linked in and try to load the i915
module, fail since it is not there, but still wait for a whole minute
before giving up binding with it.

This fixes such as case by only waiting for the binding if the module
was properly loaded (or module support is disabled, in which case i915
is already compiled-in anyway).

Fixes: f9b54e1961 ("ALSA: hda/i915: Allow delayed i915 audio component binding")
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2019-07-27 08:31:46 +02:00

153 lines
3.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* hdac_i915.c - routines for sync between HD-A core and i915 display driver
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <sound/core.h>
#include <sound/hdaudio.h>
#include <sound/hda_i915.h>
#include <sound/hda_register.h>
static struct completion bind_complete;
#define CONTROLLER_IN_GPU(pci) (((pci)->device == 0x0a0c) || \
((pci)->device == 0x0c0c) || \
((pci)->device == 0x0d0c) || \
((pci)->device == 0x160c))
/**
* snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
* @bus: HDA core bus
*
* 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.
*
* Call this function at initializing and changing power well, as well as
* at ELD notifier for the hotplug.
*/
void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
{
struct drm_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;
}
snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
}
EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);
static int i915_component_master_match(struct device *dev, int subcomponent,
void *data)
{
return !strcmp(dev->driver->name, "i915") &&
subcomponent == I915_COMPONENT_AUDIO;
}
/* check whether intel graphics is present */
static bool i915_gfx_present(void)
{
static const struct pci_device_id ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
.class = PCI_BASE_CLASS_DISPLAY << 16,
.class_mask = 0xff << 16 },
{}
};
return pci_dev_present(ids);
}
static int i915_master_bind(struct device *dev,
struct drm_audio_component *acomp)
{
complete_all(&bind_complete);
/* clear audio_ops here as it was needed only for completion call */
acomp->audio_ops = NULL;
return 0;
}
static const struct drm_audio_component_audio_ops i915_init_ops = {
.master_bind = i915_master_bind
};
/**
* snd_hdac_i915_init - Initialize i915 audio component
* @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.
*
* This function initializes and sets up the audio component to communicate
* with i915 graphics driver.
*
* Returns zero for success or a negative error code.
*/
int snd_hdac_i915_init(struct hdac_bus *bus)
{
struct drm_audio_component *acomp;
int err;
if (!i915_gfx_present())
return -ENODEV;
init_completion(&bind_complete);
err = snd_hdac_acomp_init(bus, &i915_init_ops,
i915_component_master_match,
sizeof(struct i915_audio_component) - sizeof(*acomp));
if (err < 0)
return err;
acomp = bus->audio_component;
if (!acomp)
return -ENODEV;
if (!acomp->ops) {
if (!IS_ENABLED(CONFIG_MODULES) ||
!request_module("i915")) {
/* 60s timeout */
wait_for_completion_timeout(&bind_complete,
msecs_to_jiffies(60 * 1000));
}
}
if (!acomp->ops) {
dev_info(bus->dev, "couldn't bind with audio component\n");
snd_hdac_acomp_exit(bus);
return -ENODEV;
}
return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_i915_init);