From a651261ac74298535f6d6316ebe27beceb6b17b1 Mon Sep 17 00:00:00 2001 From: Markus Schneider-Pargmann Date: Mon, 5 Aug 2024 20:30:41 +0200 Subject: [PATCH] can: m_can: Reset coalescing during suspend/resume MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit During resume the interrupts are limited to IR_RF0N and the chip keeps running. In this case if coalescing is enabled and active we may miss waterlevel interrupts during suspend. It is safer to reset the coalescing by stopping the timer and adding IR_RF0N | IR_TEFN to the interrupts. This is a theoratical issue and probably extremely rare. Cc: Martin Hundebøll Fixes: 4a94d7e31cf5 ("can: m_can: allow keeping the transceiver running in suspend") Signed-off-by: Markus Schneider-Pargmann Link: https://lore.kernel.org/all/20240805183047.305630-2-msp@baylibre.com Signed-off-by: Marc Kleine-Budde --- drivers/net/can/m_can/m_can.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index cd83c8b5d4b15..31991e2f343e9 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -2430,12 +2430,15 @@ int m_can_class_suspend(struct device *dev) netif_device_detach(ndev); /* leave the chip running with rx interrupt enabled if it is - * used as a wake-up source. + * used as a wake-up source. Coalescing needs to be reset then, + * the timer is cancelled here, interrupts are done in resume. */ - if (cdev->pm_wake_source) + if (cdev->pm_wake_source) { + hrtimer_cancel(&cdev->hrtimer); m_can_write(cdev, M_CAN_IE, IR_RF0N); - else + } else { m_can_stop(ndev); + } m_can_clk_stop(cdev); } @@ -2465,6 +2468,13 @@ int m_can_class_resume(struct device *dev) return ret; if (cdev->pm_wake_source) { + /* Restore active interrupts but disable coalescing as + * we may have missed important waterlevel interrupts + * between suspend and resume. Timers are already + * stopped in suspend. Here we enable all interrupts + * again. + */ + cdev->active_interrupts |= IR_RF0N | IR_TEFN; m_can_write(cdev, M_CAN_IE, cdev->active_interrupts); } else { ret = m_can_start(ndev); -- 2.47.2