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SubjectRE: [PATCH v2] media: imx-jpeg: Disable some unused interrupt
Date
> From: Mirela Rabulea (OSS) <mirela.rabulea@oss.nxp.com>
> Sent: 2022年6月6日 17:41
> To: Ming Qian <ming.qian@nxp.com>; mchehab@kernel.org;
> hverkuil-cisco@xs4all.nl
> Cc: shawnguo@kernel.org; s.hauer@pengutronix.de; kernel@pengutronix.de;
> festevam@gmail.com; dl-linux-imx <linux-imx@nxp.com>;
> linux-media@vger.kernel.org; linux-kernel@vger.kernel.org;
> devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org
> Subject: Re: [PATCH v2] media: imx-jpeg: Disable some unused interrupt
>
>
>
> On 06.06.2022 05:33, Ming Qian wrote:
> >> From: Mirela Rabulea (OSS) <mirela.rabulea@oss.nxp.com>
> >> Sent: 2022年6月6日 0:43
> >> To: Ming Qian <ming.qian@nxp.com>; mchehab@kernel.org;
> >> hverkuil-cisco@xs4all.nl
> >> Cc: shawnguo@kernel.org; s.hauer@pengutronix.de;
> >> kernel@pengutronix.de; festevam@gmail.com; dl-linux-imx
> >> <linux-imx@nxp.com>; linux-media@vger.kernel.org;
> >> linux-kernel@vger.kernel.org; devicetree@vger.kernel.org;
> >> linux-arm-kernel@lists.infradead.org
> >> Subject: Re: [PATCH v2] media: imx-jpeg: Disable some unused
> >> interrupt
> >>
> >> Hi Ming,
> >>
> >> On 30.05.2022 10:47, Ming Qian wrote:
> >>> The interrupt STMBUF_HALF may be triggered after frame done.
> >>> It may led to system hang if driver try to access the register after
> >>> power off.
> >>> And interrupt STMBUF_HALF and STMBUF_RTND have no other effect.
> >>> So disable them and the unused interrupts.
> >>>
> >>> Fixes: 2db16c6ed72ce ("media: imx-jpeg: Add V4L2 driver for i.MX8
> >>> JPEG
> >>> Encoder/Decoder")
> >>> Signed-off-by: Ming Qian <ming.qian@nxp.com>
> >>> ---
> >>> v2
> >>> - add Fixes tag
> >>> drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.c | 2 +-
> >>> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.c
> >>> b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.c
> >>> index c482228262a3..258fbee7ab66 100644
> >>> --- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.c
> >>> +++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg-hw.c
> >>> @@ -76,7 +76,7 @@ void print_wrapper_info(struct device *dev, void
> >>> __iomem *reg)
> >>>
> >>> void mxc_jpeg_enable_irq(void __iomem *reg, int slot)
> >>> {
> >>> - writel(0xFFFFFFFF, reg + MXC_SLOT_OFFSET(slot, SLOT_IRQ_EN));
> >>> + writel(0xF0C, reg + MXC_SLOT_OFFSET(slot, SLOT_IRQ_EN));
> >>
> >> There is another way, less aggressive, to go around this, disable all
> >> the interrupts once FRMDONE is received (or some other error
> >> condition), interrupts will get re-enabled at the next device_run. I
> >> checked this works, in
> >> mxc_jpeg_dec_irq:
> >> buffers_done:
> >> writel(0x0, reg + MXC_SLOT_OFFSET(slot, SLOT_IRQ_EN));
> >>
> >
> > Hi Mirela,
> >
> > Yes, I think it should work if we disable slot interrupt when frame done.
> > And which solution do you prefer?
>
> Hi Ming, I don't have a strong preference, but just in case we decide to later
> use some of these interrupts, I would suggest to go with the disabling after
> FRMDONE.
>
> Please do not forget to clean the other code related to "Instance released
> before the end of transaction".
>
> Thanks,
> Mirela
>

OK, I'll make another patch that disable slot interrupt when frame done, and clean the code.

> >
> > Ming
> >
> >> Either way, I would also replace this:
> >> if (!ctx) {
> >> dev_err(dev,
> >> "Instance released before the end of transaction.\n");
> >> /* soft reset only resets internal state, not registers */
> >> mxc_jpeg_sw_reset(reg);
> >> /* clear all interrupts */
> >> writel(0xFFFFFFFF, reg + MXC_SLOT_OFFSET(slot, SLOT_STATUS));
> >> goto job_unlock;
> >> }
> >>
> >> With something like:
> >> BUG_ON(!ctx)
> >>
> >> The initial intent of this code was to cope with the same problem,
> >> STMBUF_HALF interrupt received after FRMDONE, which could not be
> >> cleared, but it was not done right, I can see the hang in some rare
> >> cases. We should not run into it anymore, with interrupts disabled,
> >> either the way you proposed, or mine.
> >>
> >> Regards,
> >> Mirela
> >>
> >>> }
> >>>
> >>> void mxc_jpeg_sw_reset(void __iomem *reg)
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