forked from Minki/linux
ea9d0d771f
DPCM can update the FE/BE connection states totally asynchronously from the FE's PCM state. Most of FE/BE state changes are protected by mutex, so that they won't race, but there are still some actions that are uncovered. For example, suppose to switch a BE while a FE's stream is running. This would call soc_dpcm_runtime_update(), which sets FE's runtime_update flag, then sets up and starts BEs, and clears FE's runtime_update flag again. When a device emits XRUN during this operation, the PCM core triggers snd_pcm_stop(XRUN). Since the trigger action is an atomic ops, this isn't blocked by the mutex, thus it kicks off DPCM's trigger action. It eventually updates and clears FE's runtime_update flag while soc_dpcm_runtime_update() is running concurrently, and it results in confusion. Usually, for avoiding such a race, we take a lock. There is a PCM stream lock for that purpose. However, as already mentioned, the trigger action is atomic, and we can't take the lock for the whole soc_dpcm_runtime_update() or other operations that include the lengthy jobs like hw_params or prepare. This patch provides an alternative solution. This adds a way to defer the conflicting trigger callback to be executed at the end of FE/BE state changes. For doing it, two things are introduced: - Each runtime_update state change of FEs is protected via PCM stream lock. - The FE's trigger callback checks the runtime_update flag. If it's not set, the trigger action is executed there. If set, mark the pending trigger action and returns immediately. - At the exit of runtime_update state change, it checks whether the pending trigger is present. If yes, it executes the trigger action at this point. Reported-and-tested-by: Qiao Zhou <zhouqiao@marvell.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org |
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| .. | ||
| adi | ||
| atmel | ||
| au1x | ||
| bcm | ||
| blackfin | ||
| cirrus | ||
| codecs | ||
| davinci | ||
| dwc | ||
| fsl | ||
| generic | ||
| intel | ||
| jz4740 | ||
| kirkwood | ||
| mxs | ||
| nuc900 | ||
| omap | ||
| pxa | ||
| rockchip | ||
| s6000 | ||
| samsung | ||
| sh | ||
| sirf | ||
| spear | ||
| tegra | ||
| txx9 | ||
| ux500 | ||
| Kconfig | ||
| Makefile | ||
| soc-cache.c | ||
| soc-compress.c | ||
| soc-core.c | ||
| soc-dapm.c | ||
| soc-devres.c | ||
| soc-generic-dmaengine-pcm.c | ||
| soc-io.c | ||
| soc-jack.c | ||
| soc-pcm.c | ||
| soc-utils.c | ||