[PATCH v3 0/4] drm/qxl: fix some driver shutdown issues.

[PATCH v3 0/4] drm/qxl: fix some driver shutdown issues.

[Gerd Hoffmann]

Some progress.  Not complete though, I still
get an unclean mm warning on shutdown due to
some release objects not being freed yet.

Gerd Hoffmann (4):
  drm/qxl: use drmm_mode_config_init
  drm/qxl: unpin release objects
  drm/qxl: release shadow on shutdown
  drm/qxl: handle shadow in primary destroy

 drivers/gpu/drm/qxl/qxl_display.c | 11 +++++++++--
 drivers/gpu/drm/qxl/qxl_release.c |  1 +
 2 files changed, 10 insertions(+), 2 deletions(-)

-- 
2.29.2


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[PATCH v3 1/4] drm/qxl: use drmm_mode_config_init

[Gerd Hoffmann]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/qxl/qxl_display.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 012bce0cdb65..38d6b596094d 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -1195,7 +1195,9 @@ int qxl_modeset_init(struct qxl_device *qdev)
 	int i;
 	int ret;
 
-	drm_mode_config_init(&qdev->ddev);
+	ret = drmm_mode_config_init(&qdev->ddev);
+	if (ret)
+		return ret;
 
 	ret = qxl_create_monitors_object(qdev);
 	if (ret)
@@ -1228,5 +1230,4 @@ int qxl_modeset_init(struct qxl_device *qdev)
 void qxl_modeset_fini(struct qxl_device *qdev)
 {
 	qxl_destroy_monitors_object(qdev);
-	drm_mode_config_cleanup(&qdev->ddev);
 }
-- 
2.29.2

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Re: [PATCH v3 1/4] drm/qxl: use drmm_mode_config_init

[Thomas Zimmermann]

[-- Attachment #1.1.1: Type: text/plain, Size: 1255 bytes --]



Am 20.01.21 um 12:12 schrieb Gerd Hoffmann:
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>

> ---
>   drivers/gpu/drm/qxl/qxl_display.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
> index 012bce0cdb65..38d6b596094d 100644
> --- a/drivers/gpu/drm/qxl/qxl_display.c
> +++ b/drivers/gpu/drm/qxl/qxl_display.c
> @@ -1195,7 +1195,9 @@ int qxl_modeset_init(struct qxl_device *qdev)
>   	int i;
>   	int ret;
>   
> -	drm_mode_config_init(&qdev->ddev);
> +	ret = drmm_mode_config_init(&qdev->ddev);
> +	if (ret)
> +		return ret;
>   
>   	ret = qxl_create_monitors_object(qdev);
>   	if (ret)
> @@ -1228,5 +1230,4 @@ int qxl_modeset_init(struct qxl_device *qdev)
>   void qxl_modeset_fini(struct qxl_device *qdev)
>   {
>   	qxl_destroy_monitors_object(qdev);
> -	drm_mode_config_cleanup(&qdev->ddev);
>   }
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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[PATCH v3 2/4] drm/qxl: unpin release objects

[Gerd Hoffmann]

Balances the qxl_create_bo(..., pinned=true, ...);
call in qxl_release_bo_alloc().

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/qxl/qxl_release.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index 0fcfc952d5e9..add979cba11b 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -166,6 +166,7 @@ qxl_release_free_list(struct qxl_release *release)
 		entry = container_of(release->bos.next,
 				     struct qxl_bo_list, tv.head);
 		bo = to_qxl_bo(entry->tv.bo);
+		bo->tbo.pin_count = 0; /* ttm_bo_unpin(&bo->tbo); */
 		qxl_bo_unref(&bo);
 		list_del(&entry->tv.head);
 		kfree(entry);
-- 
2.29.2

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Re: [PATCH v3 2/4] drm/qxl: unpin release objects

[Thomas Zimmermann]

[-- Attachment #1.1.1: Type: text/plain, Size: 1456 bytes --]

Hi

Am 20.01.21 um 12:12 schrieb Gerd Hoffmann:
> Balances the qxl_create_bo(..., pinned=true, ...);
> call in qxl_release_bo_alloc().
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>   drivers/gpu/drm/qxl/qxl_release.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
> index 0fcfc952d5e9..add979cba11b 100644
> --- a/drivers/gpu/drm/qxl/qxl_release.c
> +++ b/drivers/gpu/drm/qxl/qxl_release.c
> @@ -166,6 +166,7 @@ qxl_release_free_list(struct qxl_release *release)
>   		entry = container_of(release->bos.next,
>   				     struct qxl_bo_list, tv.head);
>   		bo = to_qxl_bo(entry->tv.bo);
> +		bo->tbo.pin_count = 0; /* ttm_bo_unpin(&bo->tbo); */

This code looks like a workaround or a bug.

AFAICT the only place with pre-pinned BO is qdev->dumb_shadow_bo. Can 
you remove the pinned flag entirely and handle pinning as part of 
dumb_shadow_bo's code.

Otherwise maybe use

if (pin_count)
     ttm_bo_unpin();
WARN_ON(pin_count); /* should always be 0 now */

with a comment similar to the commit's description.

Best regards
Thomas

>   		qxl_bo_unref(&bo);
>   		list_del(&entry->tv.head);
>   		kfree(entry);
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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Re: [PATCH v3 2/4] drm/qxl: unpin release objects

[Gerd Hoffmann]

On Fri, Jan 22, 2021 at 09:13:42AM +0100, Thomas Zimmermann wrote:
> Hi
> 
> Am 20.01.21 um 12:12 schrieb Gerd Hoffmann:
> > Balances the qxl_create_bo(..., pinned=true, ...);
> > call in qxl_release_bo_alloc().
> > 
> > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> > ---
> >   drivers/gpu/drm/qxl/qxl_release.c | 1 +
> >   1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
> > index 0fcfc952d5e9..add979cba11b 100644
> > --- a/drivers/gpu/drm/qxl/qxl_release.c
> > +++ b/drivers/gpu/drm/qxl/qxl_release.c
> > @@ -166,6 +166,7 @@ qxl_release_free_list(struct qxl_release *release)
> >   		entry = container_of(release->bos.next,
> >   				     struct qxl_bo_list, tv.head);
> >   		bo = to_qxl_bo(entry->tv.bo);
> > +		bo->tbo.pin_count = 0; /* ttm_bo_unpin(&bo->tbo); */
> 
> This code looks like a workaround or a bug.
> 
> AFAICT the only place with pre-pinned BO is qdev->dumb_shadow_bo. Can you
> remove the pinned flag entirely and handle pinning as part of
> dumb_shadow_bo's code.

No, the release objects are pinned too, and they must be
pinned (qxl commands are in there, and references are
placed in the qxl rings, so allowing them to roam is
a non-starter).

> if (pin_count)
>     ttm_bo_unpin();
> WARN_ON(pin_count); /* should always be 0 now */

Well, the pin_count is 1 at this point.
No need for the if().

Just calling ttm_bo_unpin() here makes lockdep unhappy.

Not calling ttm_bo_unpin() makes ttm_bo_release() throw
a WARN() because of the pin.

Clearing pin_count (which is how ttm fixes things up
in the error path) works.

I'm open to better ideas.

take care,
  Gerd

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Re: [PATCH v3 2/4] drm/qxl: unpin release objects

[Daniel Vetter]

On Fri, Jan 22, 2021 at 2:35 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> On Fri, Jan 22, 2021 at 09:13:42AM +0100, Thomas Zimmermann wrote:
> > Hi
> >
> > Am 20.01.21 um 12:12 schrieb Gerd Hoffmann:
> > > Balances the qxl_create_bo(..., pinned=true, ...);
> > > call in qxl_release_bo_alloc().
> > >
> > > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> > > ---
> > >   drivers/gpu/drm/qxl/qxl_release.c | 1 +
> > >   1 file changed, 1 insertion(+)
> > >
> > > diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
> > > index 0fcfc952d5e9..add979cba11b 100644
> > > --- a/drivers/gpu/drm/qxl/qxl_release.c
> > > +++ b/drivers/gpu/drm/qxl/qxl_release.c
> > > @@ -166,6 +166,7 @@ qxl_release_free_list(struct qxl_release *release)
> > >             entry = container_of(release->bos.next,
> > >                                  struct qxl_bo_list, tv.head);
> > >             bo = to_qxl_bo(entry->tv.bo);
> > > +           bo->tbo.pin_count = 0; /* ttm_bo_unpin(&bo->tbo); */
> >
> > This code looks like a workaround or a bug.
> >
> > AFAICT the only place with pre-pinned BO is qdev->dumb_shadow_bo. Can you
> > remove the pinned flag entirely and handle pinning as part of
> > dumb_shadow_bo's code.
>
> No, the release objects are pinned too, and they must be
> pinned (qxl commands are in there, and references are
> placed in the qxl rings, so allowing them to roam is
> a non-starter).
>
> > if (pin_count)
> >     ttm_bo_unpin();
> > WARN_ON(pin_count); /* should always be 0 now */
>
> Well, the pin_count is 1 at this point.
> No need for the if().
>
> Just calling ttm_bo_unpin() here makes lockdep unhappy.

How does that one splat? But yeah if that's a problem should be
explained in the comment. I'd then also only do a pin_count--; to make
sure you can still catch other pin leaks if you have them. Setting it
to 0 kinda defeats the warning.
-Daniel

>
> Not calling ttm_bo_unpin() makes ttm_bo_release() throw
> a WARN() because of the pin.
>
> Clearing pin_count (which is how ttm fixes things up
> in the error path) works.
>
> I'm open to better ideas.
>
> take care,
>   Gerd
>
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Re: [PATCH v3 2/4] drm/qxl: unpin release objects

[Gerd Hoffmann]

> > Just calling ttm_bo_unpin() here makes lockdep unhappy.
> 
> How does that one splat? But yeah if that's a problem should be
> explained in the comment. I'd then also only do a pin_count--; to make
> sure you can still catch other pin leaks if you have them. Setting it
> to 0 kinda defeats the warning.

Figured the unpin is at the completely wrong place while trying to
reproduce the lockdep splat ...

take care,
  Gerd

From 43befab4a935114e8620af62781666fa81288255 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Mon, 25 Jan 2021 13:10:50 +0100
Subject: [PATCH] drm/qxl: unpin release objects

Balances the qxl_create_bo(..., pinned=true, ...);
call in qxl_release_bo_alloc().

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/qxl/qxl_release.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index c52412724c26..28013fd1f8ea 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -347,6 +347,7 @@ int qxl_alloc_release_reserved(struct qxl_device *qdev, unsigned long size,
 
 	mutex_lock(&qdev->release_mutex);
 	if (qdev->current_release_bo_offset[cur_idx] + 1 >= releases_per_bo[cur_idx]) {
+		qxl_bo_unpin(qdev->current_release_bo[cur_idx]);
 		qxl_bo_unref(&qdev->current_release_bo[cur_idx]);
 		qdev->current_release_bo_offset[cur_idx] = 0;
 		qdev->current_release_bo[cur_idx] = NULL;
-- 
2.29.2

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[PATCH v3 3/4] drm/qxl: release shadow on shutdown

[Gerd Hoffmann]

In case we have a shadow surface on shutdown release
it so it doesn't leak.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/qxl/qxl_display.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 38d6b596094d..60331e31861a 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -1229,5 +1229,9 @@ int qxl_modeset_init(struct qxl_device *qdev)
 
 void qxl_modeset_fini(struct qxl_device *qdev)
 {
+	if (qdev->dumb_shadow_bo) {
+		drm_gem_object_put(&qdev->dumb_shadow_bo->tbo.base);
+		qdev->dumb_shadow_bo = NULL;
+	}
 	qxl_destroy_monitors_object(qdev);
 }
-- 
2.29.2

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Re: [PATCH v3 3/4] drm/qxl: release shadow on shutdown

[Thomas Zimmermann]

[-- Attachment #1.1.1: Type: text/plain, Size: 1098 bytes --]

Hi

Am 20.01.21 um 12:12 schrieb Gerd Hoffmann:
> In case we have a shadow surface on shutdown release
> it so it doesn't leak.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>   drivers/gpu/drm/qxl/qxl_display.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
> index 38d6b596094d..60331e31861a 100644
> --- a/drivers/gpu/drm/qxl/qxl_display.c
> +++ b/drivers/gpu/drm/qxl/qxl_display.c
> @@ -1229,5 +1229,9 @@ int qxl_modeset_init(struct qxl_device *qdev)
>   
>   void qxl_modeset_fini(struct qxl_device *qdev)
>   {
> +	if (qdev->dumb_shadow_bo) {

Wrt to my comment on patch 2, this might be the place to unpin the BO.

> +		drm_gem_object_put(&qdev->dumb_shadow_bo->tbo.base);
> +		qdev->dumb_shadow_bo = NULL;
> +	}
>   	qxl_destroy_monitors_object(qdev);
>   }
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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[PATCH v3 4/4] drm/qxl: handle shadow in primary destroy

[Gerd Hoffmann]

qxl_primary_atomic_disable must check whenever the framebuffer bo has a
shadow surface and in case it has check the shadow primary status.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/qxl/qxl_display.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 60331e31861a..f5ee8cd72b5b 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -562,6 +562,8 @@ static void qxl_primary_atomic_disable(struct drm_plane *plane,
 	if (old_state->fb) {
 		struct qxl_bo *bo = gem_to_qxl_bo(old_state->fb->obj[0]);
 
+		if (bo->shadow)
+			bo = bo->shadow;
 		if (bo->is_primary) {
 			qxl_io_destroy_primary(qdev);
 			bo->is_primary = false;
-- 
2.29.2

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