On Wed, Feb 21, 2024 at 11:00:24AM +0800, Baochen Qiang wrote: > ath11k fails to resume: > > ath11k_pci 0000:06:00.0: timeout while waiting for restart complete > > This happens because when calling mhi_sync_power_up() the MHI subsystem > eventually calls device_add() from mhi_create_devices() but the device > creation is deferred: > > mhi mhi0_IPCR: Driver qcom_mhi_qrtr force probe deferral > > The reason for deferring device creation is explained in dpm_prepare(): > > /* > * It is unsafe if probing of devices will happen during suspend or > * hibernation and system behavior will be unpredictable in this case. > * So, let's prohibit device's probing here and defer their probes > * instead. The normal behavior will be restored in dpm_complete(). > */ > > Because the device probe is deferred, the qcom_mhi_qrtr_probe() is not > called and thus MHI channels are not prepared: > > So what this means that QRTR is not delivering messages and the QMI connection > is not working between ath11k and the firmware, resulting a failure in firmware > initialization. > > To fix this add new function mhi_power_down_no_destroy() which doesn't destroy > the devices for channels during power down. This way we avoid probe defer issue > and finally can get ath11k hibernation working with the following patches. > Upto this line is the actual commit message and below should be moved to the comments section of the patch. > Actually there is an RFC version of this change and it gets positive results > from multiple users. Firstly Mani doesn't like this idea and insists that an > MHI device should be destroyed when going to suspend/hibernation, see > > https://lore.kernel.org/mhi/20231127162022.518834-1-kvalo@xxxxxxxxxx/ > > Then Mani changed his mind after a further discussion with kernel PM guys, > see > > https://lore.kernel.org/all/21cd2098-97e1-4947-a5bb-a97582902ead@xxxxxxxxxxx/ > > So we come up with the regular version and it is almost identical with that RFC > version. > > Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30 > > Signed-off-by: Kalle Valo <quic_kvalo@xxxxxxxxxxx> > Signed-off-by: Baochen Qiang <quic_bqiang@xxxxxxxxxxx> > --- > drivers/bus/mhi/host/internal.h | 4 +++- > drivers/bus/mhi/host/pm.c | 36 +++++++++++++++++++++++++++------ > include/linux/mhi.h | 15 +++++++++++++- > 3 files changed, 47 insertions(+), 8 deletions(-) > > diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h > index 091244cf17c6..8ce4aec56425 100644 > --- a/drivers/bus/mhi/host/internal.h > +++ b/drivers/bus/mhi/host/internal.h > @@ -86,6 +86,7 @@ enum dev_st_transition { > DEV_ST_TRANSITION_FP, > DEV_ST_TRANSITION_SYS_ERR, > DEV_ST_TRANSITION_DISABLE, > + DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE, > DEV_ST_TRANSITION_MAX, > }; > > @@ -96,7 +97,8 @@ enum dev_st_transition { > dev_st_trans(MISSION_MODE, "MISSION MODE") \ > dev_st_trans(FP, "FLASH PROGRAMMER") \ > dev_st_trans(SYS_ERR, "SYS ERROR") \ > - dev_st_trans_end(DISABLE, "DISABLE") > + dev_st_trans(DISABLE, "DISABLE") \ > + dev_st_trans_end(DISABLE_DESTROY_DEVICE, "DISABLE (DESTROY DEVICE)") > > extern const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX]; > #define TO_DEV_STATE_TRANS_STR(state) (((state) >= DEV_ST_TRANSITION_MAX) ? \ > diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c > index 8b40d3f01acc..5686d32f7458 100644 > --- a/drivers/bus/mhi/host/pm.c > +++ b/drivers/bus/mhi/host/pm.c > @@ -468,7 +468,8 @@ static int mhi_pm_mission_mode_transition(struct mhi_controller *mhi_cntrl) > } > > /* Handle shutdown transitions */ > -static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl) > +static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl, > + bool destroy_device) > { > enum mhi_pm_state cur_state; > struct mhi_event *mhi_event; > @@ -530,8 +531,10 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl) > dev_dbg(dev, "Waiting for all pending threads to complete\n"); > wake_up_all(&mhi_cntrl->state_event); > > - dev_dbg(dev, "Reset all active channels and remove MHI devices\n"); > - device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device); I'd be nice to add a comment here on why destroying the device is optional. > + if (destroy_device) { > + dev_dbg(dev, "Reset all active channels and remove MHI devices\n"); > + device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device); > + } > > mutex_lock(&mhi_cntrl->pm_mutex); > > @@ -821,7 +824,10 @@ void mhi_pm_st_worker(struct work_struct *work) > mhi_pm_sys_error_transition(mhi_cntrl); > break; > case DEV_ST_TRANSITION_DISABLE: > - mhi_pm_disable_transition(mhi_cntrl); > + mhi_pm_disable_transition(mhi_cntrl, false); > + break; > + case DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE: > + mhi_pm_disable_transition(mhi_cntrl, true); > break; > default: > break; > @@ -1175,7 +1181,8 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl) > } > EXPORT_SYMBOL_GPL(mhi_async_power_up); > > -void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) > +static void __mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful, > + bool destroy_device) > { > enum mhi_pm_state cur_state, transition_state; > struct device *dev = &mhi_cntrl->mhi_dev->dev; > @@ -1211,15 +1218,32 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) > write_unlock_irq(&mhi_cntrl->pm_lock); > mutex_unlock(&mhi_cntrl->pm_mutex); > > - mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE); > + if (destroy_device) > + mhi_queue_state_transition(mhi_cntrl, > + DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE); > + else > + mhi_queue_state_transition(mhi_cntrl, > + DEV_ST_TRANSITION_DISABLE); > > /* Wait for shutdown to complete */ > flush_work(&mhi_cntrl->st_worker); > > disable_irq(mhi_cntrl->irq[0]); > } > + > +void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful) > +{ > + __mhi_power_down(mhi_cntrl, graceful, true); > +} > EXPORT_SYMBOL_GPL(mhi_power_down); > > +void mhi_power_down_no_destroy(struct mhi_controller *mhi_cntrl, How about "mhi_power_down_keep_dev"? Not the best of the API naming suggestion, but it reflects what the API does. > + bool graceful) > +{ > + __mhi_power_down(mhi_cntrl, graceful, false); > +} > +EXPORT_SYMBOL_GPL(mhi_power_down_no_destroy); > + > int mhi_sync_power_up(struct mhi_controller *mhi_cntrl) > { > int ret = mhi_async_power_up(mhi_cntrl); > diff --git a/include/linux/mhi.h b/include/linux/mhi.h > index 474d32cb0520..39a6a944a52c 100644 > --- a/include/linux/mhi.h > +++ b/include/linux/mhi.h > @@ -647,12 +647,25 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl); > int mhi_sync_power_up(struct mhi_controller *mhi_cntrl); > > /** > - * mhi_power_down - Start MHI power down sequence > + * mhi_power_down - Start MHI power down sequence. See also How about? /** * mhi_power_down - Power down the MHI device and also destroy the * 'struct device' for the channels associated with it. ... * See also mhi_power_down_keep_dev() which is a variant of * this API that keeps the 'struct device' for channels (useful during * suspend/hibernation). */ > + * mhi_power_down_no_destroy() which is a variant of this for > + * suspend/hibernation. > + * > * @mhi_cntrl: MHI controller > * @graceful: Link is still accessible, so do a graceful shutdown process > */ > void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful); > > +/** > + * mhi_power_down_no_destroy - Start MHI power down sequence but don't destroy > + * struct devices for channels. This is a variant for mhi_power_down() and > + * would be useful in suspend/hibernation. > + * /** * mhi_power_down_keep_dev - Power down the MHI device but keep the * 'struct device' for the channels * associated with it. ... * This is a variant of 'mhi_power_down' and useful in scenarios such as * suspend/hibernation where destroying of the 'struct device' is not * needed. */ - Mani > + * @mhi_cntrl: MHI controller > + * @graceful: Link is still accessible, so do a graceful shutdown process > + */ > +void mhi_power_down_no_destroy(struct mhi_controller *mhi_cntrl, bool graceful); > + > /** > * mhi_unprepare_after_power_down - Free any allocated memory after power down > * @mhi_cntrl: MHI controller > -- > 2.25.1 > > -- மணிவண்ணன் சதாசிவம்
