On Wed, Jan 29, 2025 at 01:46:15PM +0200, Abel Vesa wrote: > For historical reasons, the GLINK smem interrupt is registered with > IRRQF_NO_SUSPEND flag set, which is the underlying problem here, since the > incoming messages can be delivered during late suspend and early > resume. > > In this specific case, the pmic_glink_altmode_worker() currently gets > scheduled on the system_wq which can be scheduled to run while devices > are still suspended. This proves to be a problem when a Type-C retimer, > switch or mux that is controlled over a bus like I2C, because the I2C > controller is suspended. > > This has been proven to be the case on the X Elite boards where such > retimers (ParadeTech PS8830) are used in order to handle Type-C > orientation and altmode configuration. The following warning is thrown: > > [ 35.134876] i2c i2c-4: Transfer while suspended > [ 35.143865] WARNING: CPU: 0 PID: 99 at drivers/i2c/i2c-core.h:56 __i2c_transfer+0xb4/0x57c [i2c_core] > [ 35.352879] Workqueue: events pmic_glink_altmode_worker [pmic_glink_altmode] > [ 35.360179] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > [ 35.455242] Call trace: > [ 35.457826] __i2c_transfer+0xb4/0x57c [i2c_core] (P) > [ 35.463086] i2c_transfer+0x98/0xf0 [i2c_core] > [ 35.467713] i2c_transfer_buffer_flags+0x54/0x88 [i2c_core] > [ 35.473502] regmap_i2c_write+0x20/0x48 [regmap_i2c] > [ 35.478659] _regmap_raw_write_impl+0x780/0x944 > [ 35.483401] _regmap_bus_raw_write+0x60/0x7c > [ 35.487848] _regmap_write+0x134/0x184 > [ 35.491773] regmap_write+0x54/0x78 > [ 35.495418] ps883x_set+0x58/0xec [ps883x] > [ 35.499688] ps883x_sw_set+0x60/0x84 [ps883x] > [ 35.504223] typec_switch_set+0x48/0x74 [typec] > [ 35.508952] pmic_glink_altmode_worker+0x44/0x1fc [pmic_glink_altmode] > [ 35.515712] process_scheduled_works+0x1a0/0x2d0 > [ 35.520525] worker_thread+0x2a8/0x3c8 > [ 35.524449] kthread+0xfc/0x184 > [ 35.527749] ret_from_fork+0x10/0x20 > > The proper solution here should be to not deliver these kind of messages > during system suspend at all, or at least make it configurable per glink > client. But simply dropping the IRQF_NO_SUSPEND flag entirely will break > other clients. The final shape of the rework of the pmic glink driver in > order to fulfill both the filtering of the messages that need to be able > to wake-up the system and the queueing of these messages until the system > has properly resumed is still being discussed and it is planned as a > future effort. > > Meanwhile, the stop-gap fix here is to schedule the pmic glink altmode > worker on the system_freezable_wq instead of the system_wq. This will > result in the altmode worker not being scheduled to run until the > devices are resumed first, which will give the controllers like I2C a > chance to resume before the transfer is requested. > > Reported-by: Johan Hovold <johan+linaro@xxxxxxxxxx> > Closes: https://lore.kernel.org/lkml/Z1CCVjEZMQ6hJ-wK@xxxxxxxxxxxxxxxxxxxx/ > Fixes: 080b4e24852b ("soc: qcom: pmic_glink: Introduce altmode support") > Cc: stable@xxxxxxxxxxxxxxx # 6.3 > Reviewed-by: Caleb Connolly <caleb.connolly@xxxxxxxxxx> > Signed-off-by: Abel Vesa <abel.vesa@xxxxxxxxxx> Reviewed-by: Bjorn Andersson <andersson@xxxxxxxxxx> Regards, Bjorn > --- > Changes in v2: > - Re-worded the commit to explain the underlying problem and how > this fix is just a stop-gap for the pmic glink client for now. > - Added Johan's Reported-by tag and link > - Added Caleb's Reviewed-by tag > - Link to v1: https://lore.kernel.org/r/20250110-soc-qcom-pmic-glink-fix-device-access-on-worker-while-suspended-v1-1-e32fd6bf322e@xxxxxxxxxx > --- > drivers/soc/qcom/pmic_glink_altmode.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/soc/qcom/pmic_glink_altmode.c b/drivers/soc/qcom/pmic_glink_altmode.c > index bd06ce16180411059e9efb14d9aeccda27744280..bde129aa7d90a39becaa720376c0539bcaa492fb 100644 > --- a/drivers/soc/qcom/pmic_glink_altmode.c > +++ b/drivers/soc/qcom/pmic_glink_altmode.c > @@ -295,7 +295,7 @@ static void pmic_glink_altmode_sc8180xp_notify(struct pmic_glink_altmode *altmod > alt_port->mode = mode; > alt_port->hpd_state = hpd_state; > alt_port->hpd_irq = hpd_irq; > - schedule_work(&alt_port->work); > + queue_work(system_freezable_wq, &alt_port->work); > } > > #define SC8280XP_DPAM_MASK 0x3f > @@ -338,7 +338,7 @@ static void pmic_glink_altmode_sc8280xp_notify(struct pmic_glink_altmode *altmod > alt_port->mode = mode; > alt_port->hpd_state = hpd_state; > alt_port->hpd_irq = hpd_irq; > - schedule_work(&alt_port->work); > + queue_work(system_freezable_wq, &alt_port->work); > } > > static void pmic_glink_altmode_callback(const void *data, size_t len, void *priv) > > --- > base-commit: da7e6047a6264af16d2cb82bed9b6caa33eaf56a > change-id: 20250110-soc-qcom-pmic-glink-fix-device-access-on-worker-while-suspended-af54c5e43ed6 > > Best regards, > -- > Abel Vesa <abel.vesa@xxxxxxxxxx> >
