From 22568e8f13a42ab69b7d624741768cbf15dded74 Mon Sep 17 00:00:00 2001 From: Qingtao Cao Date: Wed, 3 Jun 2026 11:06:11 +1000 Subject: [PATCH] bus: mhi: core: Fix sys error transition latency Bring forward the idea to fix the power down latency in mhi_pm_disable_transition() further to mhi_pm_sys_error_transition() so that the transition into system error (triggered by AT!RESET) in the modems won't have to return only after the timeout of up to 24 seconds. Once the device gets reset, there is no guarantee that it will send an interrupt to indicate the state transition. So polling is the sensible option here. Signed-off-by: Qingtao Cao [mani: commit log] Signed-off-by: Manivannan Sadhasivam Reviewed-by: Krishna Chaitanya Chundru Link: https://patch.msgid.link/20260603011333.3306102-2-qingtao.cao.au@gmail.com --- drivers/bus/mhi/host/pm.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-) diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c index f799503c8f36..9d29f1591a45 100644 --- a/drivers/bus/mhi/host/pm.c +++ b/drivers/bus/mhi/host/pm.c @@ -651,21 +651,13 @@ static void mhi_pm_sys_error_transition(struct mhi_controller *mhi_cntrl) /* Trigger MHI RESET so that the device will not access host memory */ if (reset_device) { - u32 in_reset = -1; - unsigned long timeout = msecs_to_jiffies(mhi_cntrl->timeout_ms); - dev_dbg(dev, "Triggering MHI Reset in device\n"); mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET); /* Wait for the reset bit to be cleared by the device */ - ret = wait_event_timeout(mhi_cntrl->state_event, - mhi_read_reg_field(mhi_cntrl, - mhi_cntrl->regs, - MHICTRL, - MHICTRL_RESET_MASK, - &in_reset) || - !in_reset, timeout); - if (!ret || in_reset) { + ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL, + MHICTRL_RESET_MASK, 0, 25000, mhi_cntrl->timeout_ms); + if (ret) { dev_err(dev, "Device failed to exit MHI Reset state\n"); write_lock_irq(&mhi_cntrl->pm_lock); cur_state = mhi_tryset_pm_state(mhi_cntrl,