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> --- 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>
