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SubjectRE: [PATCH v2] media: imx-jpeg: Disable some unused interrupt
Date
This patch can be superseded now.
It was replaced by another patch https://patchwork.linuxtv.org/project/linux-media/patch/20220607072315.23209-1-ming.qian@nxp.com/


> From: Ming Qian
> Sent: 2022年6月7日 9:49
> To: Mirela Rabulea (OSS) <mirela.rabulea@oss.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
>
> > 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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