Re: [PATCH v7 04/12] iommu/mediatek: Add device_link between the consumer and the larb devices

["Yong Wu (吴勇)" <Yong.Wu@mediatek.com>]

On Thu, 2021-08-05 at 15:22 +0200, Dafna Hirschfeld wrote:
> 
> On 30.07.21 04:52, Yong Wu wrote:
> > MediaTek IOMMU-SMI diagram is like below. all the consumer connect
> > with
> > smi-larb, then connect with smi-common.
> > 
> >          M4U
> >           |
> >      smi-common
> >           |
> >    -------------
> >    |         |    ...
> >    |         |
> > larb1     larb2
> >    |         |
> > vdec       venc
> > 
> > When the consumer works, it should enable the smi-larb's power
> > which
> > also need enable the smi-common's power firstly.
> > 
> > Thus, First of all, use the device link connect the consumer and
> > the
> > smi-larbs. then add device link between the smi-larb and smi-
> > common.
> > 
> > This patch adds device_link between the consumer and the larbs.
> > 
> > When device_link_add, I add the flag DL_FLAG_STATELESS to avoid
> > calling
> > pm_runtime_xx to keep the original status of clocks. It can avoid
> > two
> > issues:
> > 1) Display HW show fastlogo abnormally reported in [1]. At the
> > beggining,
> > all the clocks are enabled before entering kernel, but the clocks
> > for
> > display HW(always in larb0) will be gated after clk_enable and
> > clk_disable
> > called from device_link_add(->pm_runtime_resume) and rpm_idle. The
> > clock
> > operation happened before display driver probe. At that time, the
> > display
> > HW will be abnormal.
> > 
> > 2) A deadlock issue reported in [2]. Use DL_FLAG_STATELESS to skip
> > pm_runtime_xx to avoid the deadlock.
> > 
> > Corresponding, DL_FLAG_AUTOREMOVE_CONSUMER can't be added, then
> > device_link_removed should be added explicitly.
> > 
> > [1] 
> > https://lore.kernel.org/linux-mediatek/1564213888.22908.4.camel@mhfsdcap03/
> > [2] https://lore.kernel.org/patchwork/patch/1086569/
> > 
> > Suggested-by: Tomasz Figa <tfiga@chromium.org>
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > Tested-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com> # on
> > mt8173
> 
> Hi, unfortunately, I have to take back the Tested-by tag.

sorry for inconvenience you.

(and sorry for reply late, there is something wrong about my local mail
server.)

> I am now testing the mtk-vcodec with latest kernel + patches sent
> from the mailing list:
> 
https://gitlab.collabora.com/eballetbo/linux/-/commits/topic/chromeos/chromeos-5.14
> which includes this patchset.
> 
> On chromeos I open a video conference with googl-meet which cause the
> mtk-vcodec vp8 encoder to run.
> If I kill it with `killall -9 chrome` I get some page fault messages
> from the iommu:

Does the "git bisect" point to this patch?

If you don't kill it, Does it also have these error below?

I don't know what happen about "killall -9 chrome', Does it cause
freeing some buffer?

> 
> [  837.255952] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read

This means "larb0 port0" translation fault. 

If I am not wrong, you work at mt8173, from [0], this is DISP_OVL0.

May be "killall -9 chrome" free the buffer(iova:0xfcff0000) that
DISP_OVL is accessing, then iommu complain it is not a valid iova.

[0] 
https://elixir.bootlin.com/linux/v5.14-rc1/source/include/dt-bindings/memory/mt8173-larb-port.h#L19

> [  837.265696] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
> [  837.282367] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
> [  837.299028] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
> [  837.315683] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
> [  837.332345] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
> [  837.349004] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
> [  837.365665] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
> [  837.382329] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
> [  837.400002] mtk-iommu 10205000.iommu: fault type=0x5
> iova=0xfcff0001 pa=0x0 larb=0 port=0 layer=1 read
> 
> In addition, running the encoder tests from the shell:
> 
> sudo --user=#1000 /usr/local/libexec/chrome-binary-
> tests/video_encode_accelerator_tests --
> gtest_filter=VideoEncoderTest.FlushAtEndOfStream_Multiple*  
> --codec=vp8
> /usr/local/share/tast/data/chromiumos/tast/local/bundles/cros/video/d
> ata/tulip2-320x180.yuv --disable_validator
> 
> At some point it fails with the error
> 
> [ 5472.161821] [MTK_V4L2][ERROR] mtk_vcodec_wait_for_done_ctx:32:
> [290] ctx->type=1, cmd=1, wait_event_interruptible_timeout
> time=1000ms out 0 0!
> [ 5472.174678] [MTK_VCODEC][ERROR][290]: vp8_enc_encode_frame()
> irq_status=0 failed
> [ 5472.182687] [MTK_V4L2][ERROR] mtk_venc_worker:1239: venc_if_encode
> failed=-5

+our venc guy Irui.

This looks VENC HW don't start to work. Does this caused by this
patchset?  this patchset only change the flow of power.

I guess we should check if the power/clock for venc here is enable or
not?

> 
> 
> If you have any idea of what might be the problem or how to debug?
> 
> Thanks,
> Dafna
> 
> > --