From: Joel Stanley <joel@jms.id.au>
To: Zev Weiss <zev@bewilderbeest.net>
Cc: Eddie James <eajames@linux.ibm.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Andrew Jeffery <andrew@aj.id.au>,
linux-media@vger.kernel.org,
OpenBMC Maillist <openbmc@lists.ozlabs.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-aspeed <linux-aspeed@lists.ozlabs.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Subject: Re: [PATCH 2/3] aspeed-video: clear spurious interrupt bits unconditionally
Date: Tue, 22 Dec 2020 04:47:37 +0000 [thread overview]
Message-ID: <CACPK8XczCUgqOENABoDbc-qwbMxOh=1OUyBtuHSmDG_Zo571Wg@mail.gmail.com> (raw)
In-Reply-To: <20201215024542.18888-3-zev@bewilderbeest.net>
On Tue, 15 Dec 2020 at 02:46, Zev Weiss <zev@bewilderbeest.net> wrote:
>
> Instead of testing and conditionally clearing them one by one, we can
> instead just unconditionally clear them all at once.
>
> Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
I had a poke at the assembly and it looks like GCC is clearing the
bits unconditionally anyway, so removing the tests provides no change.
Combining them is a good further optimization.
Reviewed-by: Joel Stanley <joel@jms.id.au>
A question unrelated to this patch: Do you know why the driver doesn't
clear the status bits in the interrupt handler? I would expect it to
write the value of sts back to the register to ack the pending
interrupt.
> ---
> drivers/media/platform/aspeed-video.c | 19 ++++++++++---------
> 1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c
> index eb02043532e3..218aae3be809 100644
> --- a/drivers/media/platform/aspeed-video.c
> +++ b/drivers/media/platform/aspeed-video.c
> @@ -558,6 +558,14 @@ static void aspeed_video_irq_res_change(struct aspeed_video *video, ulong delay)
> schedule_delayed_work(&video->res_work, delay);
> }
>
> +/*
> + * Interrupts that we don't use but have to explicitly ignore because the
> + * hardware asserts them even when they're disabled in the VE_INTERRUPT_CTRL
> + * register.
> + */
> +#define VE_SPURIOUS_IRQS \
> + (VE_INTERRUPT_CAPTURE_COMPLETE | VE_INTERRUPT_FRAME_COMPLETE)
> +
> static irqreturn_t aspeed_video_irq(int irq, void *arg)
> {
> struct aspeed_video *video = arg;
> @@ -630,15 +638,8 @@ static irqreturn_t aspeed_video_irq(int irq, void *arg)
> aspeed_video_start_frame(video);
> }
>
> - /*
> - * CAPTURE_COMPLETE and FRAME_COMPLETE interrupts come even when these
> - * are disabled in the VE_INTERRUPT_CTRL register so clear them to
> - * prevent unnecessary interrupt calls.
> - */
> - if (sts & VE_INTERRUPT_CAPTURE_COMPLETE)
> - sts &= ~VE_INTERRUPT_CAPTURE_COMPLETE;
> - if (sts & VE_INTERRUPT_FRAME_COMPLETE)
> - sts &= ~VE_INTERRUPT_FRAME_COMPLETE;
> + /* Squash known bogus interrupts */
> + sts &= ~VE_SPURIOUS_IRQS;
>
> if (sts)
> dev_err_ratelimited(video->dev, "unexpected interrupt asserted:"
> --
> 2.29.2
>
next prev parent reply other threads:[~2020-12-22 4:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-15 2:45 [PATCH 0/3] aspeed-video: extend spurious interrupt handling Zev Weiss
2020-12-15 2:45 ` [PATCH 1/3] aspeed-video: add error message for unhandled interrupts Zev Weiss
2020-12-22 4:34 ` Joel Stanley
2020-12-22 19:11 ` Zev Weiss
2020-12-15 2:45 ` [PATCH 2/3] aspeed-video: clear spurious interrupt bits unconditionally Zev Weiss
2020-12-22 4:47 ` Joel Stanley [this message]
2020-12-22 19:14 ` Zev Weiss
2020-12-23 1:07 ` Joel Stanley
2020-12-23 2:53 ` Ryan Chen
2020-12-23 3:53 ` Zev Weiss
2020-12-23 5:58 ` Ryan Chen
2020-12-15 2:45 ` [PATCH 3/3] aspeed-video: add COMP_READY to VE_SPURIOUS_IRQS Zev Weiss
2020-12-22 4:49 ` Joel Stanley
2021-03-09 16:43 ` Jae Hyun Yoo
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