From 1de434e0b2757061b09b347264f1ff5bdf996e58 Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Tue, 26 Mar 2024 12:12:04 +0100 Subject: [PATCH] drm/panthor: Fix ordering in _irq_suspend() Make sure we set suspended=true last to avoid generating an irq storm in the unlikely case where an IRQ happens between the suspended=true assignment and the _INT_MASK update. We also move the mask=0 assignment before writing to the _INT_MASK register to prevent the thread handler from unmasking the interrupt behind our back. This means we might lose events if there were some pending when we get to suspend the IRQ, but that's fine. The synchronize_irq() we have in the _irq_suspend() path was not there to make sure all IRQs are processed, just to make sure we don't have registers accesses coming from the irq handlers after _irq_suspend() has been called. If there's a need to have all pending IRQs processed, it should happen before _irq_suspend() is called. v3: - Add Steve's R-b v2: - New patch Fixes: 5fe909cae118 ("drm/panthor: Add the device logical block") Reported-by: Steven Price Signed-off-by: Boris Brezillon Reviewed-by: Steven Price Acked-by: Liviu Dudau Link: https://patchwork.freedesktop.org/patch/msgid/20240326111205.510019-2-boris.brezillon@collabora.com --- drivers/gpu/drm/panthor/panthor_device.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/panthor/panthor_device.h +++ b/drivers/gpu/drm/panthor/panthor_device.h @@ -325,7 +325,7 @@ static inline void panthor_ ## __name ## { \ int cookie; \ \ - atomic_set(&pirq->suspended, true); \ + pirq->mask = 0; \ \ if (drm_dev_enter(&pirq->ptdev->base, &cookie)) { \ gpu_write(pirq->ptdev, __reg_prefix ## _INT_MASK, 0); \ @@ -333,7 +333,7 @@ static inline void panthor_ ## __name ## drm_dev_exit(cookie); \ } \ \ - pirq->mask = 0; \ + atomic_set(&pirq->suspended, true); \ } \ \ static inline void panthor_ ## __name ## _irq_resume(struct panthor_irq *pirq, u32 mask) \