Re: [PATCH 2/4] media: rkisp1: Fix IRQ handler return values

Adam Ford
2023-12-05T12:35:38Z

On Tue, Dec 5, 2023 at 6:02 AM Tomi Valkeinen
<tomi.valkeinen@ideasonboard.com> wrote:
>
> On 05/12/2023 13:57, Adam Ford wrote:
> > On Tue, Dec 5, 2023 at 2:10 AM Tomi Valkeinen
> > <tomi.valkeinen@ideasonboard.com> wrote:
> >>
> >> The IRQ handler rkisp1_isr() calls sub-handlers, all of which returns an
> >> irqreturn_t value, but rkisp1_isr() ignores those values and always
> >> returns IRQ_HANDLED.
> >>
> >> Fix this by collecting the return values, and returning IRQ_HANDLED or
> >> IRQ_NONE as appropriate.
> >>
> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> >> ---
> >> drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c | 18 ++++++++++++++----
> >> 1 file changed, 14 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> >> index 76f93614b4cf..1d60f4b8bd09 100644
> >> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> >> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-dev.c
> >> @@ -445,17 +445,27 @@ static int rkisp1_entities_register(struct rkisp1_device *rkisp1)
> >>
> >> static irqreturn_t rkisp1_isr(int irq, void *ctx)
> >> {
> >> + irqreturn_t ret;
> >> +
> >> /*
> >> * Call rkisp1_capture_isr() first to handle the frame that
> >> * potentially completed using the current frame_sequence number before
> >> * it is potentially incremented by rkisp1_isp_isr() in the vertical
> >> * sync.
> >> */
> >> - rkisp1_capture_isr(irq, ctx);
> >> - rkisp1_isp_isr(irq, ctx);
> >> - rkisp1_csi_isr(irq, ctx);
> >>
> >> - return IRQ_HANDLED;
> >> + ret = IRQ_NONE;
> >> +
> >> + if (rkisp1_capture_isr(irq, ctx) == IRQ_HANDLED)
> >> + ret = IRQ_HANDLED;
> >> +
> >> + if (rkisp1_isp_isr(irq, ctx) == IRQ_HANDLED)
> >> + ret = IRQ_HANDLED;
> >> +
> >> + if (rkisp1_csi_isr(irq, ctx) == IRQ_HANDLED)
> >> + ret = IRQ_HANDLED;
> >> +
> >
> > It seems like we're throwing away the value of ret each time the
> > subsequent if statement is evaluated. Whether or not they return
> > didn't matter before, and the only one that seems using the return
> > code is the last one.
> >
> > Wouldn't it be simpler to use ret = rkisp1_capture_isr(irq, ctx), ret
> > = rkisp1_isp_isr(irq, ctx) and ret = rkisp1_csi_isr(irq, ctx) if we
> > care about the return code?
> >
> > How do you expect this to return if one of the first two don't return
> > IRQ_HANDLED?
>
> I'm sorry, I don't quite follow what you mean. Can you elaborate a bit?
>
> We want the rkisp1_isr() to return IRQ_NONE if none of the sub-handlers
> handled the interrupt. Otherwise, if any of the sub-handlers return
> IRQ_HANDLED, rkisp1_isr() returns IRQ_HANDLED.

OK. I understand your explanation. I retract my comment. I'll try
to test this series tonight on my imx8mp

adam

>
> Tomi