[PATCH 1/3] agp/intel-gtt: Don't leak the scratch page

[PATCH 1/3] agp/intel-gtt: Don't leak the scratch page

[Daniel Vetter]

Recently discovered by enabling CONFIG_DMA_API_DEBUG in our CI. By the
looks of it broken since forever.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93793
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/char/agp/intel-gtt.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 1341a94cc779..432ae61a8715 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -1430,6 +1430,14 @@ void intel_gmch_remove(void)
 	if (--intel_private.refcount)
 		return;
 
+	if (intel_private.scratch_page) {
+		if (intel_private.needs_dmar)
+			pci_unmap_page(intel_private.pcidev,
+				       intel_private.scratch_page_dma,
+				       PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
+
+		__free_page(intel_private.scratch_page);
+	}
 	if (intel_private.pcidev)
 		pci_dev_put(intel_private.pcidev);
 	if (intel_private.bridge_dev)
-- 
2.5.0

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[PATCH 2/3] drm/i915: Stop depending upon CONFIG_AGP/_INTEL

[Daniel Vetter]

We need this to be able to paper over some CI fail: DMA API debuggin
complaints that we leak the gmch scratch page, but fundamentally
that's the only way to do it if there's both the intel-agp and i915
driver using it: intel-agp shadow-attaches, i915 binds for real to the
gpu. But when i915 unloads we need to keep the dma-mapping for
intel-agp around, and the dma debugging code doesn't approve of that.

With this patch we can disable CONFIG_AGP_INTEL and avoid this
troubel.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93769
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/i915/Kconfig | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
index fcd77b27514d..9aa7d2d98add 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -2,9 +2,7 @@ config DRM_I915
 	tristate "Intel 8xx/9xx/G3x/G4x/HD Graphics"
 	depends on DRM
 	depends on X86 && PCI
-	depends on (AGP || AGP=n)
 	select INTEL_GTT
-	select AGP_INTEL if AGP
 	select INTERVAL_TREE
 	# we need shmfs for the swappable backing store, and in particular
 	# the shmem_readpage() which depends upon tmpfs
-- 
2.5.0

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[PATCH 3/3] agp/intel-gtt: Only register fake agp driver for gen1

[Daniel Vetter]

The fake agp driver for the intel graphics gart is only needed for ums
support. And we ditched that a long time ago:

commit 03dae59c72ffffd8ef6e005f48ba356c863e0587
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Jul 23 16:27:25 2014 +0200

    drm/i915: Ditch UMS config option

With this there's no longer the problem that 2 drivers (fake agp
driver and the drm/i915 driver) fight over the same piece, which fixes
apparent dma leaks detected by CONFIG_DMA_API_DEBUG.

Note that the leak isn't real since intel-gtt refcounts and will tear
down eventually. But the debug code assumes that when the i915 driver
unbinds from the pci device everything should be gone. Which isn't the
case if we have intel-agp enabled - userspace might need it. But by
ditching this intel-gtt setup and teardown is completely tied to the
livetime of the "real" driver.

While at it untangle the init ordering a bit - the fake agp wouldn't
be initialized correctly if i915.ko loads first. Which isn't a problem
since when i915 loads in kms mode you won't need the fake agp support
needed by the ums driver ...

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93793
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/char/agp/intel-gtt.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 432ae61a8715..1b5e07258d80 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -1346,16 +1346,6 @@ int intel_gmch_probe(struct pci_dev *bridge_pdev, struct pci_dev *gpu_pdev,
 {
 	int i, mask;
 
-	/*
-	 * Can be called from the fake agp driver but also directly from
-	 * drm/i915.ko. Hence we need to check whether everything is set up
-	 * already.
-	 */
-	if (intel_private.driver) {
-		intel_private.refcount++;
-		return 1;
-	}
-
 	for (i = 0; intel_gtt_chipsets[i].name != NULL; i++) {
 		if (gpu_pdev) {
 			if (gpu_pdev->device ==
@@ -1376,16 +1366,26 @@ int intel_gmch_probe(struct pci_dev *bridge_pdev, struct pci_dev *gpu_pdev,
 	if (!intel_private.driver)
 		return 0;
 
-	intel_private.refcount++;
-
 #if IS_ENABLED(CONFIG_AGP_INTEL)
 	if (bridge) {
+		if (INTEL_GTT_GEN > 1)
+			return 0;
+
 		bridge->driver = &intel_fake_agp_driver;
 		bridge->dev_private_data = &intel_private;
 		bridge->dev = bridge_pdev;
 	}
 #endif
 
+
+	/*
+	 * Can be called from the fake agp driver but also directly from
+	 * drm/i915.ko. Hence we need to check whether everything is set up
+	 * already.
+	 */
+	if (intel_private.refcount++)
+		return 1;
+
 	intel_private.bridge_dev = pci_dev_get(bridge_pdev);
 
 	dev_info(&bridge_pdev->dev, "Intel %s Chipset\n", intel_gtt_chipsets[i].name);
-- 
2.5.0

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Re: [PATCH 2/3] drm/i915: Stop depending upon CONFIG_AGP/_INTEL

[Chris Wilson]

On Tue, Jan 26, 2016 at 07:49:55PM +0100, Daniel Vetter wrote:
> We need this to be able to paper over some CI fail: DMA API debuggin
> complaints that we leak the gmch scratch page, but fundamentally
> that's the only way to do it if there's both the intel-agp and i915
> driver using it: intel-agp shadow-attaches, i915 binds for real to the
> gpu. But when i915 unloads we need to keep the dma-mapping for
> intel-agp around, and the dma debugging code doesn't approve of that.
> 
> With this patch we can disable CONFIG_AGP_INTEL and avoid this
> troubel.

How about:

The AGP_INTEL driver provides an interface for very old userspace to
control the GART (though the GART itself was only ever emulated on Intel
systems). The pci bridge discovery code is also used by the i915.ko
driver to set up the GTT on old systems, but it does not require the
old userspace interface. When i915.ko selects the old interface, it
binds another user to the core GTT routines, and in particular creates a
second reference to the scratch pages allocated. This hinders resource
leak debugging for when we unload i915.ko as we want to assert that all
DMA pages have been released, but we appear to leak because of the
secondary interface which persists after i915.ko unloads.

All i915.ko users do not require the old /dev/agpgart interface so stop
selecting it and simplify our debugging by dropping the historical
baggage.
-Chris

-- 
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Re: [PATCH 3/3] agp/intel-gtt: Only register fake agp driver for gen1

[Chris Wilson]

On Tue, Jan 26, 2016 at 07:49:56PM +0100, Daniel Vetter wrote:
> The fake agp driver for the intel graphics gart is only needed for ums
> support. And we ditched that a long time ago:
> 
> commit 03dae59c72ffffd8ef6e005f48ba356c863e0587
> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> Date:   Wed Jul 23 16:27:25 2014 +0200
> 
>     drm/i915: Ditch UMS config option
> 
> With this there's no longer the problem that 2 drivers (fake agp
> driver and the drm/i915 driver) fight over the same piece, which fixes
> apparent dma leaks detected by CONFIG_DMA_API_DEBUG.
> 
> Note that the leak isn't real since intel-gtt refcounts and will tear
> down eventually. But the debug code assumes that when the i915 driver
> unbinds from the pci device everything should be gone. Which isn't the
> case if we have intel-agp enabled - userspace might need it. But by
> ditching this intel-gtt setup and teardown is completely tied to the
> livetime of the "real" driver.
> 
> While at it untangle the init ordering a bit - the fake agp wouldn't
> be initialized correctly if i915.ko loads first. Which isn't a problem
> since when i915 loads in kms mode you won't need the fake agp support
> needed by the ums driver ...
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93793
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris

-- 
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Re: [PATCH 1/3] agp/intel-gtt: Don't leak the scratch page

[Chris Wilson]

On Tue, Jan 26, 2016 at 07:49:54PM +0100, Daniel Vetter wrote:
> Recently discovered by enabling CONFIG_DMA_API_DEBUG in our CI. By the
> looks of it broken since forever.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93793
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>  drivers/char/agp/intel-gtt.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
> index 1341a94cc779..432ae61a8715 100644
> --- a/drivers/char/agp/intel-gtt.c
> +++ b/drivers/char/agp/intel-gtt.c
> @@ -1430,6 +1430,14 @@ void intel_gmch_remove(void)
>  	if (--intel_private.refcount)
>  		return;
>  
> +	if (intel_private.scratch_page) {

The page (for who knows what reason) is set to uc. We need to restore it
back to wb before releasing it.

> +		if (intel_private.needs_dmar)
> +			pci_unmap_page(intel_private.pcidev,
> +				       intel_private.scratch_page_dma,
> +				       PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
> +

set_pages_wb(intel_private.scratch_page, 1);

> +		__free_page(intel_private.scratch_page);
> +	}
>  	if (intel_private.pcidev)
>  		pci_dev_put(intel_private.pcidev);
>  	if (intel_private.bridge_dev)

-- 
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Re: [PATCH 2/3] drm/i915: Stop depending upon CONFIG_AGP/_INTEL

[Ville Syrjälä]

On Tue, Jan 26, 2016 at 07:49:55PM +0100, Daniel Vetter wrote:
> We need this to be able to paper over some CI fail: DMA API debuggin
> complaints that we leak the gmch scratch page, but fundamentally
> that's the only way to do it if there's both the intel-agp and i915
> driver using it: intel-agp shadow-attaches, i915 binds for real to the
> gpu. But when i915 unloads we need to keep the dma-mapping for
> intel-agp around, and the dma debugging code doesn't approve of that.
> 
> With this patch we can disable CONFIG_AGP_INTEL and avoid this
> troubel.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93769
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>  drivers/gpu/drm/i915/Kconfig | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
> index fcd77b27514d..9aa7d2d98add 100644
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -2,9 +2,7 @@ config DRM_I915
>  	tristate "Intel 8xx/9xx/G3x/G4x/HD Graphics"
>  	depends on DRM
>  	depends on X86 && PCI
> -	depends on (AGP || AGP=n)
>  	select INTEL_GTT
> -	select AGP_INTEL if AGP

Just setting AGP=n in .config isn't enough?

>  	select INTERVAL_TREE
>  	# we need shmfs for the swappable backing store, and in particular
>  	# the shmem_readpage() which depends upon tmpfs
> -- 
> 2.5.0
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
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✗ Fi.CI.BAT: failure for series starting with [1/3] agp/intel-gtt: Don't leak the scratch page

[Patchwork]

== Summary ==

Built on 430706bace599ea1a908b9a7c6b7ea17535fe17f drm-intel-nightly: 2016y-01m-27d-16h-33m-06s UTC integration manifest

Test kms_flip:
        Subgroup basic-flip-vs-dpms:
                pass       -> DMESG-WARN (ilk-hp8440p) UNSTABLE
        Subgroup basic-flip-vs-wf_vblank:
                pass       -> FAIL       (bdw-ultra)
Test kms_pipe_crc_basic:
        Subgroup hang-read-crc-pipe-a:
                pass       -> DMESG-WARN (skl-i5k-2)
        Subgroup read-crc-pipe-b:
                dmesg-warn -> PASS       (ilk-hp8440p)

bdw-nuci7        total:141  pass:132  dwarn:0   dfail:0   fail:0   skip:9  
bdw-ultra        total:144  pass:137  dwarn:0   dfail:0   fail:1   skip:6  
bsw-nuc-2        total:144  pass:120  dwarn:0   dfail:0   fail:0   skip:24 
byt-nuc          total:144  pass:129  dwarn:0   dfail:0   fail:0   skip:15 
hsw-brixbox      total:144  pass:137  dwarn:0   dfail:0   fail:0   skip:7  
hsw-gt2          total:144  pass:140  dwarn:0   dfail:0   fail:0   skip:4  
ilk-hp8440p      total:144  pass:104  dwarn:1   dfail:0   fail:1   skip:38 
ivb-t430s        total:144  pass:138  dwarn:0   dfail:0   fail:0   skip:6  
skl-i5k-2        total:144  pass:134  dwarn:2   dfail:0   fail:0   skip:8  
snb-dellxps      total:144  pass:130  dwarn:0   dfail:0   fail:0   skip:14 
snb-x220t        total:144  pass:130  dwarn:0   dfail:0   fail:1   skip:13 

Results at /archive/results/CI_IGT_test/Patchwork_1269/

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✓ Fi.CI.BAT: success for series starting with [1/3] agp/intel-gtt: Don't leak the scratch page

[Patchwork]

== Summary ==

Series 2851v1 Series without cover letter
http://patchwork.freedesktop.org/api/1.0/series/2851/revisions/1/mbox/


bdw-nuci7        total:156  pass:147  dwarn:0   dfail:0   fail:0   skip:9  
bdw-ultra        total:159  pass:153  dwarn:0   dfail:0   fail:0   skip:6  
bsw-nuc-2        total:159  pass:135  dwarn:0   dfail:0   fail:0   skip:24 
byt-nuc          total:159  pass:142  dwarn:0   dfail:0   fail:0   skip:17 
hsw-brixbox      total:159  pass:152  dwarn:0   dfail:0   fail:0   skip:7  
hsw-gt2          total:159  pass:155  dwarn:0   dfail:0   fail:0   skip:4  
ilk-hp8440p      total:159  pass:114  dwarn:0   dfail:0   fail:1   skip:44 
ivb-t430s        total:159  pass:151  dwarn:0   dfail:0   fail:0   skip:8  
skl-i5k-2        total:159  pass:150  dwarn:1   dfail:0   fail:0   skip:8  
snb-dellxps      total:159  pass:141  dwarn:0   dfail:0   fail:0   skip:18 
snb-x220t        total:159  pass:141  dwarn:0   dfail:0   fail:1   skip:17 

Results at /archive/results/CI_IGT_test/Patchwork_1298/

b3f8ad64bc71f6236f05c2e9f4ad49a61745869a drm-intel-nightly: 2016y-01m-28d-10h-26m-23s UTC integration manifest
ccf350019ee7f44491df9438405c4a7c651e5c34 agp/intel-gtt: Only register fake agp driver for gen1
27a9bfda50dca90958389412d538c923dc2653ee drm/i915: Stop depending upon CONFIG_AGP/_INTEL
f11f867f3f49d543d643b5b3487dfc54ad7a3ab2 agp/intel-gtt: Don't leak the scratch page

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