From ef8d8df3cb06fb99856bb7164b50ff52d6b07e66 Mon Sep 17 00:00:00 2001 From: Anatoliy Klymenko Date: Tue, 23 Jan 2024 18:54:01 -0800 Subject: drm: xlnx: zynqmp_dpsub: Filter interrupts against mask Filter out status register against the interrupts' mask. Some events are being reported via DP status register, even if corresponding interrupts have been disabled. One instance of such event leads to generation of VBLANK when the driver is in DRM bridge mode, which in turn results in NULL pointer dereferencing. We should avoid processing such events in an interrupt handler context. This problem is less noticeable when the driver operates in DMA mode, as in this case we have DRM CRTC object instantiated and DRM framework simply discards unwanted VBLANKs in drm_handle_vblank(). Signed-off-by: Anatoliy Klymenko Reviewed-by: Tomi Valkeinen Reviewed-by: Laurent Pinchart Signed-off-by: Tomi Valkeinen Link: https://patchwork.freedesktop.org/patch/msgid/20240124025402.373620-5-anatoliy.klymenko@amd.com --- drivers/gpu/drm/xlnx/zynqmp_dp.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/xlnx/zynqmp_dp.c') diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c index 5a3335e1fffa..9f48e5bbcdec 100644 --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c @@ -1627,7 +1627,14 @@ static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data) /* clear status register as soon as we read it */ zynqmp_dp_write(dp, ZYNQMP_DP_INT_STATUS, status); mask = zynqmp_dp_read(dp, ZYNQMP_DP_INT_MASK); - if (!(status & ~mask)) + + /* + * Status register may report some events, which corresponding interrupts + * have been disabled. Filter out those events against interrupts' mask. + */ + status &= ~mask; + + if (!status) return IRQ_NONE; /* dbg for diagnostic, but not much that the driver can do */ -- cgit v1.2.3