Hi Anatoliy, Thank you for the patch. On Tue, Jan 23, 2024 at 06:54:01PM -0800, Anatoliy Klymenko wrote: > 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 <anatoliy.klymenko@xxxxxxx> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/xlnx/zynqmp_dp.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > 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 */ -- Regards, Laurent Pinchart
