Attachment 144637 Details for Bug 110997 – Fix for Tesla i2c regression

[patch] Fix for Tesla i2c regression

0001-drm-nouveau-Enable-i2c-pads-busses-during-preinit.patch (text/plain), 2.65 KB, created by Lyude Paul on 2019-06-25 20:56:39 UTC

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Creator: Lyude Paul

Created: 2019-06-25 20:56:39 UTC

Size: 2.65 KB

patch

obsolete

>From 07bfbc3b8fadbdb8215a93bffaeefd176601bf1b Mon Sep 17 00:00:00 2001
>From: Lyude Paul <lyude@redhat.com>
>Date: Tue, 25 Jun 2019 16:53:34 -0400
>Subject: [PATCH] drm/nouveau: Enable i2c pads & busses during preinit
>
>It turns out that while disabling i2c bus access from software when the
>GPU is suspended was a step in the right direction with:
>
>commit 342406e4fbba ("drm/nouveau/i2c: Disable i2c bus access after
>->fini()")
>
>We also ended up accidentally breaking the vbios init scripts on some
>older Tesla GPUs, as apparently said scripts can actually use the i2c
>bus. Since these scripts are executed before initializing any
>subdevices, we end up failing to acquire access to the i2c bus which has
>left a number of cards with their fan controllers uninitialized. Luckily
>this doesn't break hardware - it just means the fan gets stuck at 100%.
>
>This also means that we've always been using our i2c busses before
>initializing them during the init scripts for older GPUs, we just didn't
>notice it until we started preventing them from being used until init.
>It's pretty impressive this never caused us any issues before!
>
>So, fix this by initializing our i2c pad and busses during subdev
>pre-init. We skip initializing aux busses during pre-init, as those are
>guaranteed to only ever be used by nouveau for DP aux transactions.
>
>Signed-off-by: Lyude Paul <lyude@redhat.com>
>Fixes: 342406e4fbba ("drm/nouveau/i2c: Disable i2c bus access after ->fini()")
>Cc: stable@vger.kernel.org
>---
> .../gpu/drm/nouveau/nvkm/subdev/i2c/base.c    | 20 +++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
>diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/base.c b/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/base.c
>index ecacb22834d7..719345074711 100644
>--- a/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/base.c
>+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/base.c
>@@ -184,6 +184,25 @@ nvkm_i2c_fini(struct nvkm_subdev *subdev, bool suspend)
> 	return 0;
> }
> 
>+static int
>+nvkm_i2c_preinit(struct nvkm_subdev *subdev)
>+{
>+	struct nvkm_i2c *i2c = nvkm_i2c(subdev);
>+	struct nvkm_i2c_bus *bus;
>+	struct nvkm_i2c_pad *pad;
>+
>+	/*
>+	 * We init our i2c busses as early as possible, since they may be
>+	 * needed by the vbios init scripts on some cards
>+	 */
>+	list_for_each_entry(pad, &i2c->pad, head)
>+		nvkm_i2c_pad_init(pad);
>+	list_for_each_entry(bus, &i2c->bus, head)
>+		nvkm_i2c_bus_init(bus);
>+
>+	return 0;
>+}
>+
> static int
> nvkm_i2c_init(struct nvkm_subdev *subdev)
> {
>@@ -238,6 +257,7 @@ nvkm_i2c_dtor(struct nvkm_subdev *subdev)
> static const struct nvkm_subdev_func
> nvkm_i2c = {
> 	.dtor = nvkm_i2c_dtor,
>+	.preinit = nvkm_i2c_preinit,
> 	.init = nvkm_i2c_init,
> 	.fini = nvkm_i2c_fini,
> 	.intr = nvkm_i2c_intr,
>-- 
>2.21.0
>

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Attachments on bug 110997: 144635 | 144637

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