From: Joel Stanley <joel@jms.id.au>
To: Zev Weiss <zev@bewilderbeest.net>, Ryan Chen <ryan_chen@aspeedtech.com>
Cc: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>,
linux-aspeed <linux-aspeed@lists.ozlabs.org>,
Andrew Jeffery <andrew@aj.id.au>,
OpenBMC Maillist <openbmc@lists.ozlabs.org>,
Eddie James <eajames@linux.ibm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-media@vger.kernel.org
Subject: Re: [PATCH 2/3] aspeed-video: clear spurious interrupt bits unconditionally
Date: Wed, 23 Dec 2020 01:07:12 +0000 [thread overview]
Message-ID: <CACPK8XeOZEkpAKcyhZLeMdGzbwtFmdGEnL6QXp0VK1HL_O2pSg@mail.gmail.com> (raw)
In-Reply-To: <20201222191433.3dgnfwyrod4tnvaf@hatter.bewilderbeest.net>
On Tue, 22 Dec 2020 at 19:14, Zev Weiss <zev@bewilderbeest.net> wrote:
>
> On Mon, Dec 21, 2020 at 10:47:37PM CST, Joel Stanley wrote:
> >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.
> >
>
> No, I don't, and I was sort of wondering the same thing actually -- I'm
> not deeply familiar with this hardware or driver though, so I was a bit
> hesitant to start messing with things. (Though maybe doing so would
> address the "stickiness" aspect when it does manifest.) Perhaps Eddie
> or Jae can shed some light here?
I think you're onto something here - this would be why the status bits
seem to stick until the device is reset.
Until Aspeed can clarify if this is a hardware or software issue, I
suggest we ack the bits and log a message when we see them, instead of
always ignoring them without taking any action.
Can you write a patch that changes the interrupt handler to ack status
bits as it handles each of them?
>
>
> Zev
>
next prev parent reply other threads:[~2020-12-23 1:08 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
2020-12-22 19:14 ` Zev Weiss
2020-12-23 1:07 ` Joel Stanley [this message]
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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