> -----Original Message----- > From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> > Sent: Monday, September 12, 2022 4:58 AM > To: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>; alsa-devel@xxxxxxxxxxxxxxxx; > vkoul@xxxxxxxxxx; broonie@xxxxxxxxxx > Cc: vinod.koul@xxxxxxxxxx; Liao, Bard <bard.liao@xxxxxxxxx>; linux- > kernel@xxxxxxxxxxxxxxx; Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx> > Subject: Re: [PATCH] soundwire: bus: conditionally recheck UNATTACHED status > > [top posting] > I reverted this patch in the SOF tree to use Richard Fitzgerald's > series, see > > https://github.com/thesofproject/linux/pull/3836 > > I don't think we want this patch upstream, do we? Agree, let's don't merge this upstream. > > > On 8/30/22 09:42, Bard Liao wrote: > > From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> > > > > In configurations with two amplifiers on the same link, the Intel CI > > reports occasional enumeration/initialization timeouts during > > suspend-resume stress tests, where one of the two amplifiers becomes > > UNATTACHED immediately after being enumerated. This problem was > > reported both with Maxim and Realtek codecs, which pointed initially > > to a problem with status handling on the Intel side. > > > > The Cadence IP integrated on Intel platforms throws an interrupt when > > the status changes, and the information is kept with sticky bits until > > cleared. We initially added more checks to make sure the edge > > detection did not miss any transition, but that did not improve the > > results significantly. > > > > With the recent addition of the read_ping_status() callback, we were > > able to show that the status in sticky bits is shown as UNATTACHED > > even though the PING frames show the problematic device as > > ATTACHED. That completely breaks the entire logic where we assumed > > that a peripheral would always re-attach as device0. The resume > > timeouts make sense in that in those cases, the > > enumeration/initialization never happens a second time. > > > > One possible explanation is that this problem typically happens when a > > bus clash is reported, so it could very well be that the detection is > > fooled by a transient electrical issue or conflict between two > > peripherals. > > > > This patch conditionally double-checks the status reported in the > > sticky bits with the actual PING frame status. If the peripheral > > reports as attached in PING frames, the early detection based on > > sticky bits is discarded. > > > > Note that this patch only corrects issues of false positives on the > > manager side. > > > > If the peripheral lost and regain sync, then it would report as > > attached on Device0. A peripheral that would not reset its dev_num > > would not be compliant with the MIPI specification. > > > > BugLink: https://github.com/thesofproject/linux/issues/3638 > > BugLink: https://github.com/thesofproject/linux/issues/3325 > > Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> > > Reviewed-by: Rander Wang <rander.wang@xxxxxxxxx> > > Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx> > > --- > > Hi Vinod, > > > > You will need the "ASoC/soundwire: log actual PING status on resume issues" > > series which is applied at ASoC tree before appling this patch. > > > > --- > > drivers/soundwire/bus.c | 19 +++++++++++++++++++ > > drivers/soundwire/intel.c | 1 + > > include/linux/soundwire/sdw.h | 3 +++ > > 3 files changed, 23 insertions(+) > > > > diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c > > index 2772973eebb1..d0d486f07673 100644 > > --- a/drivers/soundwire/bus.c > > +++ b/drivers/soundwire/bus.c > > @@ -1767,6 +1767,25 @@ int sdw_handle_slave_status(struct sdw_bus *bus, > > slave->status != SDW_SLAVE_UNATTACHED) { > > dev_warn(&slave->dev, "Slave %d state check1: > UNATTACHED, status was %d\n", > > i, slave->status); > > + > > + if (bus->recheck_unattached && bus->ops- > >read_ping_status) { > > + u32 ping_status; > > + > > + mutex_lock(&bus->msg_lock); > > + > > + ping_status = bus->ops->read_ping_status(bus); > > + > > + mutex_unlock(&bus->msg_lock); > > + > > + ping_status >>= (i * 2); > > + ping_status &= 0x3; > > + > > + if (ping_status != 0) { > > + dev_warn(&slave->dev, "Slave %d state > in PING frame is %d, ignoring earlier detection\n", > > + i, ping_status); > > + continue; > > + } > > + } > > sdw_modify_slave_status(slave, > SDW_SLAVE_UNATTACHED); > > } > > } > > diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c > > index 25ec9c272239..0c6e674dbf85 100644 > > --- a/drivers/soundwire/intel.c > > +++ b/drivers/soundwire/intel.c > > @@ -1311,6 +1311,7 @@ static int intel_link_probe(struct auxiliary_device > *auxdev, > > > > bus->link_id = auxdev->id; > > bus->dev_num_ida_min = INTEL_DEV_NUM_IDA_MIN; > > + bus->recheck_unattached = true; > > > > sdw_cdns_probe(cdns); > > > > diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h > > index a2b31d25ea27..51ac71984260 100644 > > --- a/include/linux/soundwire/sdw.h > > +++ b/include/linux/soundwire/sdw.h > > @@ -892,6 +892,8 @@ struct sdw_master_ops { > > * @dev_num_ida_min: if set, defines the minimum values for the IDA > > * used to allocate system-unique device numbers. This value needs to be > > * identical across all SoundWire bus in the system. > > + * @recheck_unattached: if set, double-check UNATTACHED status changes > > + * by reading PING frame status. > > */ > > struct sdw_bus { > > struct device *dev; > > @@ -917,6 +919,7 @@ struct sdw_bus { > > bool multi_link; > > int hw_sync_min_links; > > int dev_num_ida_min; > > + bool recheck_unattached; > > }; > > > > int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent,
