At Thu, 23 May 2013 09:51:07 +0800, Wang Xingchao wrote:
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
sound/pci/hda/hda_i915.c | 13 ++++-- sound/pci/hda/hda_intel.c | 105 +++++++++++++++++++++++++++------------------- 2 files changed, 71 insertions(+), 47 deletions(-)
diff --git a/sound/pci/hda/hda_i915.c b/sound/pci/hda/hda_i915.c index 76c13d5..7547b20 100644 --- a/sound/pci/hda/hda_i915.c +++ b/sound/pci/hda/hda_i915.c @@ -42,13 +42,18 @@ int hda_i915_init(void) { int err = 0;
- get_power = symbol_request(i915_request_power_well);
- get_power = symbol_get(i915_request_power_well); if (!get_power) {
snd_printk(KERN_WARNING "hda-i915: get_power symbol get fail\n");return -ENODEV;
request_module("i915");get_power = symbol_get(i915_request_power_well);if (!get_power) {snd_printk(KERN_WARNING "hda-i915: get_power symbol get fail\n");return -ENODEV;}snd_printdd("hda-i915: get_power symbol get successful\n");
Why do you need this change?
Takashi