On Thu, 10 Mar 2022 03:25:27 +0100, S.J. Wang wrote: > > Hi > > > > > > > > > > > > > > Hi Takashi Iwai, Jaroslav Kysela > > > > > > > > > > We encountered an issue in the pcm_dsnoop use case, could you > > > > > please help to have a look? > > > > > > > > > > *Issue description:* > > > > > With two instances for dsnoop type device running in parallel, > > > > > after suspend/resume, one of the instances will be hung in memcpy > > > > > because the very large copy size is obtained. > > > > > > > > > > #3 0x0000ffffa78d5098 in snd_pcm_dsnoop_sync_ptr > > > > (pcm=0xaaab06563da0) > > > > > at pcm_dsnoop.c:158 dsnoop = 0xaaab06563c20 slave_hw_ptr = 64 > > > > > old_slave_hw_ptr = 533120 avail = *187651522444320* > > > > > > > > > > * Reason analysis: * > > > > > The root cause that I analysis is that after suspend/resume, > > > > > one instance will get the SND_PCM_STATE_SUSPENDED state from slave > > > > > pcm > > > > device, > > > > > then it will do snd_pcm_prepare() and snd_pcm_start(), which > > > > > will reset the dsnoop->slave_hw_ptr and the hw_ptr of slave pcm > > > > > device, then the state of this instance is correct. But another > > > > > instance may not get the SND_PCM_STATE_SUSPENDED state from > > slave > > > > > pcm device because slave device may have been recovered by first > > > > > instance, so the dsnoop->slave_hw_ptr is not reset. but because > > > > > hw_ptr of slave pcm device has been reset, so there will be a very large > > "avail" size. > > > > > > > > > > *Solution:* > > > > > I didn't come up with a fix for this issue, seems there is no > > > > > easy way to let another instance know this case and reset the > > > > > dsnoop->slave_hw_ptr, could you please help? > > > > > > > > Could you try topic/pcm-direct-resume branch on > > > > > > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgi > > > > thub > > > > .com%2Ftiwai%2Falsa- > > > > > > lib&data=04%7C01%7Cshengjiu.wang%40nxp.com%7C95f97de3f2c840d > > > > > > 9853508d9fd2e79ea%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C > > > > > > 637819198319430045%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwM > > > > > > DAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdat > > > > > > a=WWX1ZlcQhJF3pHJdHPIH%2B0xG9o%2FjQnHG5fHDbKXwQwE%3D&r > > > > eserved=0 > > > > > > > > > > Thanks, I push my test result in > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith > > > ub.com%2Falsa-project%2Falsa- > > lib%2Fissues%2F213&data=04%7C01%7Cshe > > > > > ngjiu.wang%40nxp.com%7Cf71e70640d1b40b66be508d9fdbb2ac2%7C686ea > > 1d3bc2b > > > > > 4c6fa92cd99c5c301635%7C0%7C0%7C637819802581943763%7CUnknown%7 > > CTWFpbGZs > > > > > b3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn > > 0%3D > > > %7C3000&sdata=fZ2ogNj2RDTv4DV8vgB71M2m0XtU8UhMiXEV1%2Bl > > wUrQ%3D& > > > ;reserved=0 > > > Could you please review? > > > > Please keep the discussion on ML. > > > > I saw you have update the origin/topic/pcm-direct-resume branch, I test your > latest change, it is more stable than before, but still meet once of the issue after > overnight test, it it very very low possibility. > > So I suggest if we need to do below change, shall we? Point taken. The xrun/suspend check should be right before the slave hwptr update, yes. I updated the git repo again. Will submit the patch set for the merge as the final version. thanks, Takashi
