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Message-ID: <db9016a39f612cc93ee070c1eba4e4471a89a5cd.camel@ndufresne.ca>
Date: Tue, 03 Feb 2026 10:40:52 -0500
From: Nicolas Dufresne <nicolas@...fresne.ca>
To: "Ming Qian(OSS)" <ming.qian@....nxp.com>, Marco Felsch
<m.felsch@...gutronix.de>
Cc: linux-media@...r.kernel.org, imx@...ts.linux.dev,
ulf.hansson@...aro.org, Frank.li@....com, peng.fan@....com,
festevam@...il.com, robh@...nel.org, benjamin.gaignard@...labora.com,
sebastian.fricke@...labora.com, linux-imx@....com,
devicetree@...r.kernel.org, conor+dt@...nel.org, p.zabel@...gutronix.de,
linux-pm@...r.kernel.org, s.hauer@...gutronix.de, mchehab@...nel.org,
linux-arm-kernel@...ts.infradead.org, eagle.zhou@....com,
linux-kernel@...r.kernel.org, kernel@...gutronix.de,
hverkuil-cisco@...all.nl, krzk+dt@...nel.org, shawnguo@...nel.org,
l.stach@...gutronix.de
Subject: Re: [PATCH] arm64: dts: imx8mq: Restore VPU G2 clock to 600MHz for
4K60fps decoding
Le mardi 03 février 2026 à 16:53 +0800, Ming Qian(OSS) a écrit :
> Hi Marco,
>
> On 2/3/2026 4:31 PM, Marco Felsch wrote:
> > [You don't often get email from m.felsch@...gutronix.de. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
> >
> > Hi,
> >
> > sorry for jumping in.
> >
> > On 26-02-03, Ming Qian(OSS) wrote:
> > > Hi Nicolas,
> > >
> > > On 2/3/2026 3:12 AM, Nicolas Dufresne wrote:
> > > > Hi,
> > > >
> > > > Le lundi 02 février 2026 à 13:44 -0500, Nicolas Dufresne a écrit :
> > > > > > This doesn't sound like just a VPU issue; it's related to the display or
> > > > > > DDR.
> > > > > > If not displayed, do the fluster test cases yield different results at
> > > > > > 600MHz and 300MHz?
> > > > >
> > > > > Didn't you run these tests before sending ? I can try again, but in my
> > > > > internal
> > > > > notes, I wrote:
> > > > >
> > > > > > Tested that, and everything becomes unstable
> > > > >
> > > > > That was before I figure-out the IRQ handler didn't handle exception bits that
> > > > > didn't stop the decoder (or dry IRQ, which strangely is common from the G2).
> > > >
> > > > Ran some fluster tests now. With this patch the results is not consistent
> > > > anymore. Then I ran it with weston being started, and in the middle of the test
> > > > the display turned black. Matches my past observation. We did reproduce this on
> > > > BSP kernel too. When the display goes black, the recent hantro drivers reports:
> > > >
> > > > [ 827.581586] hantro-vpu 38310000.video-codec: frame decode timed out.
> > > > [ 827.720201] hantro-vpu 38310000.video-codec: not all macroblocks were
> > > > decoded.
> > > >
> > > >
> > > > I have local patches to reduce the cascade of errors, so it likely survived
> > > > longer then last time. I will send these patches soon. The "not all macroblocks
> > > > were decoded." is triggered by a bit in the status register that is not
> > > > documented in NXP TRM. I found that bit in some VC8000D documentation (the
> > > > sucessor of G2). I concluded it was the same meaning after looking at the failed
> > > > buffer visually, it is indeed missing couple of macroblocks near th end. Each
> > > > time we see this error, the DCSS gives up and turn either black, or sometimes
> > > > other color. The second case has been tracked to a DCSS Scaler underrun, the
> > > > first we don't know.
> > > >
> > > > Fluster command ran (two threads, never completes):
> > > >
> > > > ./fluster.py run -d GStreamer-H.265-V4L2SL-Gst1.0 -ts JCT-VC-HEVC_V1 -j2 -t90
> > > >
> > > > Nicolas
> > >
> > > My test results for fluster differ from yours.
> > > On my end, the results for JCT-VC-HEVC_V1 are consistent at both 300MHz and
> > > 600MHz.
> > > And results remained unchanged after multiple tests.
After more testing, the fluster test is stable for NV12/NV15 tiled output for me
too. I'm running the tests with linear NV12/P010, which imply an extra set of
buffer. I will check if I can give you a easy way to test the linear formats. I
also have couple of streams that systematically breaks at specific spot (high
complexity scenes) with the provided patch. As most licensed content, this is
not sharable as-is. I will try and see if I can find a way to share something.
> > >
> > > I'm not sure what caused the differences between us.
> >
> > Once it comes to system stability, you need to ensure that your
> > bootstack is aligned e.g. same TF-A version and sometimes same
> > bootloader since there might be workarounds/erratum applied by the boot
> > firmware.
> >
> > Regards,
> > Marco
> >
>
> Thanks for the reminder, and I agree.
> I think we need to align our board environment first.
I do likely have slightly different bootchain, and of course all the HDMI
component are downstream, but I can't really isolate the dramatic issue of this
overclock without a display component of some sort. Its a huge differentiator in
the bandwidth consumption which is the main challenge on this SoC so far. 10bit
videos makes things a lot worse fwiw.
We did review latest IMX vendor firmware package and can confirm we are running
the latest memory training blob and HDMI firmware.
Nicolas
> Regards,
> Ming
>
> > >
> > > Below are my test results:
> > >
> > > 600Mhz, 0.9v
> > > cat /sys/kernel/debug/regulator/regulator_summary |grep SW1C
> > > SW1C 0 1 0 unknown 900mV 0mA
> > > 825mV 1100mV
> > > cat /sys/kernel/debug/clk/vpu_g2/clk_rate
> > > 600000000
> > >
> > > ./fluster.py run -ts JCT-VC-HEVC_V1 -d GStreamer-H.265-V4L2SL-Gst1.0 -j2 -t
> > > 90
> > > ****************************************************************************************************
> > > Running test suite JCT-VC-HEVC_V1 with decoder
> > > GStreamer-H.265-V4L2SL-Gst1.0
> > > Using 2 parallel job(s)
> > > ****************************************************************************************************
> > >
> > > Ran 139/147 tests successfully in 505.434 secs
> > > Ran 139/147 tests successfully in 505.350 secs
> > > Ran 139/147 tests successfully in 507.540 secs
> > >
> > > 600Mhz, 1.0v
> > > cat /sys/kernel/debug/regulator/regulator_summary |grep SW1C
> > > SW1C 0 1 0 unknown 1000mV 0mA
> > > 825mV 1100mV
> > > cat /sys/kernel/debug/clk/vpu_g2/clk_rate
> > > 600000000
> > >
> > > ./fluster.py run -ts JCT-VC-HEVC_V1 -d GStreamer-H.265-V4L2SL-Gst1.0 -j2 -t
> > > 90
> > > Ran 139/147 tests successfully in 506.901 secs
> > >
> > > 300Mhz, 0.9v
> > > cat /sys/kernel/debug/regulator/regulator_summary |grep SW1C
> > > SW1C 0 1 0 unknown 900mV 0mA
> > > 825mV 1100mV
> > > cat /sys/kernel/debug/clk/vpu_g2/clk_rate
> > > 300000000
> > >
> > > ./fluster.py run -ts JCT-VC-HEVC_V1 -d GStreamer-H.265-V4L2SL-Gst1.0 -j2 -t
> > > 90
> > > Ran 139/147 tests successfully in 506.063 secs
> > >
> > > Downstream v4l2 driver
> > > cat /sys/kernel/debug/regulator/regulator_summary |grep SW1C
> > > SW1C 0 2 0 unknown 1000mV 0mA
> > > 825mV 1100mV
> > > cat /sys/kernel/debug/clk/vpu_g2/clk_rate
> > > 600000000
> > >
> > > ./fluster.py run -ts JCT-VC-HEVC_V1 -d GStreamer-H.265-V4L2-Gst1.0 -j2 -t
> > > 90
> > > Ran 136/147 tests successfully in 460.435 secs
> > >
> > > Regards,
> > > Ming
> > >
> > >
> >
> > --
> > #gernperDu
> > #CallMeByMyFirstName
> >
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