[PATCH v2 0/6] drm/vc4: kms: Misc fixes for HVS commits

[Jian-Hong Pan]

Maxime Ripard <maxime at cerno.tech> 於 2021年12月3日 週五 下午10:03寫道：
>
> On Mon, Nov 29, 2021 at 04:31:57PM +0800, Jian-Hong Pan wrote:
> > Maxime Ripard <maxime at cerno.tech> 於 2021年11月26日 週五 下午11:45寫道：
> > >
> > > On Fri, Nov 19, 2021 at 06:24:34PM +0800, Jian-Hong Pan wrote:
> > > > Maxime Ripard <maxime at cerno.tech> 於 2021年11月18日 週四 下午6:40寫道：
> > > > >
> > > > > On Thu, Nov 18, 2021 at 02:42:58PM +0800, Jian-Hong Pan wrote:
> > > > > > Maxime Ripard <maxime at cerno.tech> 於 2021年11月17日 週三 下午5:45寫道：
> > > > > > > The conversion to DRM commit helpers (f3c420fe19f8, "drm/vc4: kms: Convert to
> > > > > > > atomic helpers") introduced a number of issues in corner cases, most of them
> > > > > > > showing themselves in the form of either a vblank timeout or use-after-free
> > > > > > > error.
> > > > > > >
> > > > > > > These patches should fix most of them, some of them still being debugged.
> > > > > > >
> > > > > > > Maxime
> > > > > > >
> > > > > > > Changes from v1:
> > > > > > >   - Prevent a null pointer dereference
> > > > > > >
> > > > > > > Maxime Ripard (6):
> > > > > > >   drm/vc4: kms: Wait for the commit before increasing our clock rate
> > > > > > >   drm/vc4: kms: Fix return code check
> > > > > > >   drm/vc4: kms: Add missing drm_crtc_commit_put
> > > > > > >   drm/vc4: kms: Clear the HVS FIFO commit pointer once done
> > > > > > >   drm/vc4: kms: Don't duplicate pending commit
> > > > > > >   drm/vc4: kms: Fix previous HVS commit wait
> > > > > > >
> > > > > > >  drivers/gpu/drm/vc4/vc4_kms.c | 42 ++++++++++++++++-------------------
> > > > > > >  1 file changed, 19 insertions(+), 23 deletions(-)
> > > > > >
> > > > > > I tested the v2 patches based on latest mainline kernel with RPi 4B.
> > > > > > System can boot up into desktop environment.
> > > > >
> > > > > So the thing that was broken initially isn't anymore?
> > > >
> > > > No.  It does not appear anymore.
> > > >
> > > > > > Although it still hit the bug [1], which might be under debugging, I
> > > > > > think these patches LGTM.
> > > > >
> > > > > The vblank timeout stuff is a symptom of various different bugs. Can you
> > > > > share your setup, your config.txt, and what you're doing to trigger it?
> > > >
> > > > I get the RPi boot firmware files from raspberrypi's repository at tag
> > > > 1.20211029 [1]
> > > > And, make system boots:
> > > > RPi firmware -> U-Boot -> Linux kernel (aarch64) with corresponding DTB
> > > >
> > > > The config.txt only has:
> > > > enable_uart=1
> > > > arm_64bit=1
> > > > kernel=uboot.bin
> > > >
> > > > This bug can be reproduced with es2gears command easily.  May need to
> > > > wait it running a while.
> > > >
> > > > Mesa: 21.2.2
> > > > libdrm: 2.4.107
> > > > xserver/wayland: 1.20.11  Using wayland
> > > >
> > > > This bug happens with direct boot path as well:
> > > > RPi firmware -> Linux kernel (aarch64) with corresponding DTB
> > > >
> > > > I tried with Endless OS and Ubuntu's RPi 4B images.
> > > > An easy setup is using Ubuntu 21.10 RPi 4B image [2].  Then, replace
> > > > the kernel & device tree blob and edit the config.txt.
> > >
> > > Does it still appear if you raise the core clock in the config.txt file
> > > using: core_freq_min=600 ?
> >
> > It still appears when I raise the core clock in the config.txt file:
> > core_freq_min=600
>
> That's weird, we had some issues like that already but could never point
> exactly what was going on.
>
> Is testing the official raspberrypi kernel an option for you? If so,
> trying the same workload with fkms would certainly help

I tested the raspberrypi kernel on rpi-5.16.y branch at commit
bcb52df6df52 ("xhci: add a quirk to work around a suspected cache bug
on VLI controllers").  Also, enabled the fkms.  So, vc4 and v3d are
loaded.  However, the "flip_done timed out" error does not appear like
mainline kernel.

Jian-Hong Pan