ALSA: hda - Add power-welll support for haswell HDA
For Intel Haswell chip, HDA controller and codec have
power well dependency from GPU side. This patch added support
to request/release power well in audio driver. Power save
feature should be enabled to get runtime power saving.
There's deadlock when request_module(i915) in azx_probe.
It looks like:
device_lock(audio pci device) -> azx_probe -> module_request
(or symbol_request) -> modprobe (userspace) -> i915 init ->
drm_pci_init -> pci_register_driver -> bus_add_driver -> driver_attach ->
which in turn tries all locks on pci bus, and when it tries the one on the
audio device, it will deadlock.
This patch introduce a work to store remaining probe stuff, and let
request_module run in safe work context.
Signed-off-by: Wang Xingchao <xingchao.wang@linux.intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
Reviewed-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/sound/pci/hda/hda_i915.c b/sound/pci/hda/hda_i915.c
new file mode 100644
index 0000000..76c13d5
--- /dev/null
+++ b/sound/pci/hda/hda_i915.c
@@ -0,0 +1,75 @@
+/*
+ * hda_i915.c - routines for Haswell HDA controller power well support
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <sound/core.h>
+#include <drm/i915_powerwell.h>
+#include "hda_i915.h"
+
+static void (*get_power)(void);
+static void (*put_power)(void);
+
+void hda_display_power(bool enable)
+{
+ if (!get_power || !put_power)
+ return;
+
+ snd_printdd("HDA display power %s \n",
+ enable ? "Enable" : "Disable");
+ if (enable)
+ get_power();
+ else
+ put_power();
+}
+
+int hda_i915_init(void)
+{
+ int err = 0;
+
+ get_power = symbol_request(i915_request_power_well);
+ if (!get_power) {
+ snd_printk(KERN_WARNING "hda-i915: get_power symbol get fail\n");
+ return -ENODEV;
+ }
+
+ put_power = symbol_request(i915_release_power_well);
+ if (!put_power) {
+ symbol_put(i915_request_power_well);
+ get_power = NULL;
+ return -ENODEV;
+ }
+
+ snd_printd("HDA driver get symbol successfully from i915 module\n");
+
+ return err;
+}
+
+int hda_i915_exit(void)
+{
+ if (get_power) {
+ symbol_put(i915_request_power_well);
+ get_power = NULL;
+ }
+ if (put_power) {
+ symbol_put(i915_release_power_well);
+ put_power = NULL;
+ }
+
+ return 0;
+}