From: Lyude <cpaul@redhat.com>
To: amd-gfx@lists.freedesktop.org
Cc: Lyude <cpaul@redhat.com>,
stable@vger.kernel.org, "Alex Deucher" <alexdeucher@gmail.com>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Christian König" <christian.koenig@amd.com>,
"David Airlie" <airlied@linux.ie>,
"Chunming Zhou" <David1.Zhou@amd.com>,
"Jammy Zhou" <Jammy.Zhou@amd.com>, "Monk Liu" <Monk.Liu@amd.com>,
"Flora Cui" <Flora.Cui@amd.com>,
"Tom St Denis" <tom.stdenis@amd.com>,
dri-devel@lists.freedesktop.org (open list:RADEON and AMDGPU DRM
DRIVERS), linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v2] drm/amdgpu: Disable RPM helpers while reprobing connectors on resume
Date: Mon, 18 Jul 2016 11:41:37 -0400 [thread overview]
Message-ID: <1468856499-19246-1-git-send-email-cpaul@redhat.com> (raw)
Just about all of amdgpu's connector probing functions try to acquire
runtime PM refs. If we try to do this in the context of
amdgpu_resume_kms by calling drm_helper_hpd_irq_event(), we end up
deadlocking the system.
Since we're guaranteed to be holding the spinlock for RPM in
amdgpu_resume_kms, and we already know the GPU is in working order, we
need to prevent the RPM helpers from trying to run during the initial
connector reprobe on resume.
There's a couple of solutions I've explored for fixing this, but this
one by far seems to be the simplest and most reliable (plus I'm pretty
sure that's what disable_depth is there for anyway).
Reproduction recipe:
- Get any laptop dual GPUs using PRIME
- Make sure runtime PM is enabled for amdgpu
- Boot the machine
- If the machine managed to boot without hanging, switch out of X to
another VT. This should definitely cause X to hang infinitely.
Changes since v1:
- add appropriate #ifdef checks for CONFIG_PM. This is not very
useful, but it appears some kernel test suites test compiling amdgpu
with CONFIG_PM disabled, which results in this patch breaking the builds
if we don't include this #ifdef
Cc: stable@vger.kernel.org
Cc: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Lyude <cpaul@redhat.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 6e92008..b7f5650 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -1841,7 +1841,23 @@ int amdgpu_resume_kms(struct drm_device *dev, bool resume, bool fbcon)
}
drm_kms_helper_poll_enable(dev);
+
+ /*
+ * Most of the connector probing functions try to acquire runtime pm
+ * refs to ensure that the GPU is powered on when connector polling is
+ * performed. Since we're calling this from a runtime PM callback,
+ * trying to acquire rpm refs will cause us to deadlock.
+ *
+ * Since we're guaranteed to be holding the rpm lock, it's safe to
+ * temporarily disable the rpm helpers so this doesn't deadlock us.
+ */
+#ifdef CONFIG_PM
+ dev->dev->power.disable_depth++;
+#endif
drm_helper_hpd_irq_event(dev);
+#ifdef CONFIG_PM
+ dev->dev->power.disable_depth--;
+#endif
if (fbcon) {
amdgpu_fbdev_set_suspend(adev, 0);
--
2.7.4
next reply other threads:[~2016-07-18 15:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-18 15:41 Lyude [this message]
2016-07-27 20:31 ` [PATCH v2] drm/amdgpu: Disable RPM helpers while reprobing connectors on resume Alex Deucher
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1468856499-19246-1-git-send-email-cpaul@redhat.com \
--to=cpaul@redhat.com \
--cc=David1.Zhou@amd.com \
--cc=Flora.Cui@amd.com \
--cc=Jammy.Zhou@amd.com \
--cc=Monk.Liu@amd.com \
--cc=airlied@linux.ie \
--cc=alexander.deucher@amd.com \
--cc=alexdeucher@gmail.com \
--cc=amd-gfx@lists.freedesktop.org \
--cc=christian.koenig@amd.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=linux-kernel@vger.kernel.org \
--cc=stable@vger.kernel.org \
--cc=tom.stdenis@amd.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).