Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220429195350.85620-1-lyude@redhat.com> <CACO55ttsBxe6V88CTtGZgUj8k+gT+ne+FD_9FD_OxowF1XG5Bg@mail.gmail.com>
In-Reply-To: <CACO55ttsBxe6V88CTtGZgUj8k+gT+ne+FD_9FD_OxowF1XG5Bg@mail.gmail.com>
From:   Karol Herbst <kherbst@redhat.com>
Date:   Wed, 4 May 2022 00:01:34 +0200
Message-ID: <CACO55tv=u+HNKS9tH-ggy_O0YRiZQvAyb48gxRVqrz-fmWcvwA@mail.gmail.com>
Subject: Re: [PATCH] drm/nouveau/subdev/bus: Ratelimit logging for fault errors
To:     Lyude Paul <lyude@redhat.com>
Cc:     nouveau <nouveau@lists.freedesktop.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Ben Skeggs <bskeggs@redhat.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        open list <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Actually, there is another place we have to put this, we can spam
"SCHED_ERROR" things which are triggered within multiple
drivers/gpu/drm/nouveau/nvkm/engine/fifo/ files.

On Tue, May 3, 2022 at 9:23 PM Karol Herbst <kherbst@redhat.com> wrote:
>
> not able to hit any error on my machine, but regardless:
>
> Reviewed-by: Karol Herbst <kherbst@redhat.com>
>
> I suspect there are more places where we could put it, but we can add
> those later.
>
> Anyway, I think it's valuable to push it through fixes, not sure how
> far back we want to CC stable though.
>
> On Fri, Apr 29, 2022 at 9:54 PM Lyude Paul <lyude@redhat.com> wrote:
> >
> > There's plenty of ways to fudge the GPU when developing on nouveau by
> > mistake, some of which can result in nouveau seriously spamming dmesg with
> > fault errors. This can be somewhat annoying, as it can quickly overrun the
> > message buffer (or your terminal emulator's buffer) and get rid of actually
> > useful feedback from the driver. While working on my new atomic only MST
> > branch, I ran into this issue a couple of times.
> >
> > So, let's fix this by adding nvkm_error_ratelimited(), and using it to
> > ratelimit errors from faults. This should be fine for developers, since
> > it's nearly always only the first few faults that we care about seeing.
> > Plus, you can turn off rate limiting in the kernel if you really need to.
> >
> > Signed-off-by: Lyude Paul <lyude@redhat.com>
> > ---
> >  drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h |  2 ++
> >  drivers/gpu/drm/nouveau/nvkm/subdev/bus/gf100.c    | 14 +++++++-------
> >  drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv31.c     |  6 +++---
> >  drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv50.c     |  6 +++---
> >  4 files changed, 15 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h b/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
> > index 1665738948fb..96113c8bee8c 100644
> > --- a/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
> > +++ b/drivers/gpu/drm/nouveau/include/nvkm/core/subdev.h
> > @@ -62,4 +62,6 @@ void nvkm_subdev_intr(struct nvkm_subdev *);
> >  #define nvkm_debug(s,f,a...) nvkm_printk((s), DEBUG,   info, f, ##a)
> >  #define nvkm_trace(s,f,a...) nvkm_printk((s), TRACE,   info, f, ##a)
> >  #define nvkm_spam(s,f,a...)  nvkm_printk((s),  SPAM,    dbg, f, ##a)
> > +
> > +#define nvkm_error_ratelimited(s,f,a...) nvkm_printk((s), ERROR, err_ratelimited, f, ##a)
> >  #endif
> > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bus/gf100.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bus/gf100.c
> > index 53a6651ac225..80b5aaceeaad 100644
> > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bus/gf100.c
> > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bus/gf100.c
> > @@ -35,13 +35,13 @@ gf100_bus_intr(struct nvkm_bus *bus)
> >                 u32 addr = nvkm_rd32(device, 0x009084);
> >                 u32 data = nvkm_rd32(device, 0x009088);
> >
> > -               nvkm_error(subdev,
> > -                          "MMIO %s of %08x FAULT at %06x [ %s%s%s]\n",
> > -                          (addr & 0x00000002) ? "write" : "read", data,
> > -                          (addr & 0x00fffffc),
> > -                          (stat & 0x00000002) ? "!ENGINE " : "",
> > -                          (stat & 0x00000004) ? "PRIVRING " : "",
> > -                          (stat & 0x00000008) ? "TIMEOUT " : "");
> > +               nvkm_error_ratelimited(subdev,
> > +                                      "MMIO %s of %08x FAULT at %06x [ %s%s%s]\n",
> > +                                      (addr & 0x00000002) ? "write" : "read", data,
> > +                                      (addr & 0x00fffffc),
> > +                                      (stat & 0x00000002) ? "!ENGINE " : "",
> > +                                      (stat & 0x00000004) ? "PRIVRING " : "",
> > +                                      (stat & 0x00000008) ? "TIMEOUT " : "");
> >
> >                 nvkm_wr32(device, 0x009084, 0x00000000);
> >                 nvkm_wr32(device, 0x001100, (stat & 0x0000000e));
> > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv31.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv31.c
> > index ad8da523bb22..c75e463f3501 100644
> > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv31.c
> > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv31.c
> > @@ -45,9 +45,9 @@ nv31_bus_intr(struct nvkm_bus *bus)
> >                 u32 addr = nvkm_rd32(device, 0x009084);
> >                 u32 data = nvkm_rd32(device, 0x009088);
> >
> > -               nvkm_error(subdev, "MMIO %s of %08x FAULT at %06x\n",
> > -                          (addr & 0x00000002) ? "write" : "read", data,
> > -                          (addr & 0x00fffffc));
> > +               nvkm_error_ratelimited(subdev, "MMIO %s of %08x FAULT at %06x\n",
> > +                                      (addr & 0x00000002) ? "write" : "read", data,
> > +                                      (addr & 0x00fffffc));
> >
> >                 stat &= ~0x00000008;
> >                 nvkm_wr32(device, 0x001100, 0x00000008);
> > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv50.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv50.c
> > index 3a1e45adeedc..2055d0b100d3 100644
> > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv50.c
> > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bus/nv50.c
> > @@ -60,9 +60,9 @@ nv50_bus_intr(struct nvkm_bus *bus)
> >                 u32 addr = nvkm_rd32(device, 0x009084);
> >                 u32 data = nvkm_rd32(device, 0x009088);
> >
> > -               nvkm_error(subdev, "MMIO %s of %08x FAULT at %06x\n",
> > -                          (addr & 0x00000002) ? "write" : "read", data,
> > -                          (addr & 0x00fffffc));
> > +               nvkm_error_ratelimited(subdev, "MMIO %s of %08x FAULT at %06x\n",
> > +                                      (addr & 0x00000002) ? "write" : "read", data,
> > +                                      (addr & 0x00fffffc));
> >
> >                 stat &= ~0x00000008;
> >                 nvkm_wr32(device, 0x001100, 0x00000008);
> > --
> > 2.35.1
> >