[PATCH v2] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[PATCH v2] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Chris Wilson]

Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled

"Display flickering may occur when both FBC (Frame Buffer Compression)
and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
and in use by the display controller."

Ville found the w/a name in the database:
WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl

v2: Log when the quirk is applied.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h  |  2 ++
 drivers/gpu/drm/i915/intel_fbc.c | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index afe1ff67557c..02b888684de8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2577,6 +2577,8 @@ struct drm_i915_cmd_table {
 #define INTEL_GEN(p)	(INTEL_INFO(p)->gen)
 #define INTEL_DEVID(p)	(INTEL_INFO(p)->device_id)
 
+#define mkwrite_intel_info(p) ((struct intel_device_info *)INTEL_INFO(p))
+
 #define REVID_FOREVER		0xff
 #define INTEL_REVID(p)	(__I915__(p)->drm.pdev->revision)
 
diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index fddba1eed5ad..b3c67021771b 100644
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -1230,6 +1230,18 @@ void intel_fbc_init_pipe_state(struct drm_i915_private *dev_priv)
 			dev_priv->fbc.visible_pipes_mask |= (1 << crtc->pipe);
 }
 
+static bool need_fbc_wa(struct drm_i915_private *dev_priv)
+{
+#ifdef CONFIG_INTEL_IOMMU
+	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl */
+	if (intel_iommu_gfx_mapped && IS_SKYLAKE(dev_priv)) {
+		DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n");
+		return true;
+	}
+#endif
+	return false;
+}
+
 /**
  * intel_fbc_init - Initialize FBC
  * @dev_priv: the i915 device
@@ -1247,6 +1259,9 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
 	fbc->active = false;
 	fbc->work.scheduled = false;
 
+	if (need_fbc_wa(dev_priv))
+		mkwrite_intel_info(dev_priv)->has_fbc = false;
+
 	if (!HAS_FBC(dev_priv)) {
 		fbc->no_fbc_reason = "unsupported by this chipset";
 		return;
-- 
2.8.1

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[PATCH] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Chris Wilson]

Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled

"Display flickering may occur when both FBC (Frame Buffer Compression)
and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
and in use by the display controller."

Ville found the w/a name in the database:
WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl

v2: Log when the quirk is applied.
v3: Ensure i915.enable_fbc is false when !HAS_FBC()

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
---

Paulo, I was under the impression you wanted to ack this as a known
issue?
-Chris

---
 drivers/gpu/drm/i915/intel_fbc.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index 06d3a86828fc..17343baf25ea 100644
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -1240,12 +1240,28 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
 	if (i915.enable_fbc >= 0)
 		return !!i915.enable_fbc;
 
+	if (!HAS_FBC(dev_priv))
+		return 0;
+
 	if (IS_BROADWELL(dev_priv))
 		return 1;
 
 	return 0;
 }
 
+static bool need_fbc_wa(struct drm_i915_private *dev_priv)
+{
+#ifdef CONFIG_INTEL_IOMMU
+	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl */
+	if (intel_iommu_gfx_mapped && IS_SKYLAKE(dev_priv)) {
+		DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n");
+		return true;
+	}
+#endif
+
+	return false;
+}
+
 /**
  * intel_fbc_init - Initialize FBC
  * @dev_priv: the i915 device
@@ -1263,6 +1279,9 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
 	fbc->active = false;
 	fbc->work.scheduled = false;
 
+	if (need_fbc_wa(dev_priv))
+		mkwrite_intel_info(dev_priv)->has_fbc = false;
+
 	i915.enable_fbc = intel_sanitize_fbc_option(dev_priv);
 	DRM_DEBUG_KMS("Sanitized enable_fbc value: %d\n", i915.enable_fbc);
 
-- 
2.8.1

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✗ Ro.CI.BAT: failure for drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Patchwork]

== Series Details ==

Series: drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake
URL   : https://patchwork.freedesktop.org/series/10606/
State : failure

== Summary ==

  CC      drivers/pci/pci-acpi.o
  CC      drivers/pci/pcie/aer/aerdrv_core.o
  CC [M]  drivers/net/ethernet/intel/igb/e1000_nvm.o
  CC [M]  drivers/net/ethernet/intel/igbvf/netdev.o
  CC      drivers/pci/pcie/aer/aerdrv.o
  CC      drivers/pci/pcie/aer/aerdrv_acpi.o
  CC      drivers/pci/pcie/aer/ecrc.o
  CC [M]  drivers/net/ethernet/intel/igb/e1000_phy.o
  CC      drivers/pci/pci-label.o
  CC [M]  drivers/net/ethernet/intel/igb/e1000_mbx.o
  CC [M]  drivers/net/ethernet/intel/e1000e/param.o
  CC [M]  drivers/net/ethernet/intel/igb/e1000_i210.o
  LD [M]  drivers/net/ethernet/intel/e1000/e1000.o
  CC [M]  drivers/net/ethernet/intel/igb/igb_ptp.o
  CC [M]  drivers/net/ethernet/intel/igb/igb_hwmon.o
  CC [M]  drivers/net/ethernet/intel/e1000e/ethtool.o
  CC [M]  drivers/net/ethernet/intel/e1000e/netdev.o
  CC [M]  drivers/net/ethernet/intel/e1000e/ptp.o
  LD      drivers/pci/pcie/pcieportdrv.o
  LD      drivers/pci/pcie/aer/aerdriver.o
  LD      drivers/pci/pcie/aer/built-in.o
  LD      drivers/pci/pcie/built-in.o
  LD      drivers/pci/built-in.o
  LD [M]  drivers/net/ethernet/intel/igbvf/igbvf.o
  LD [M]  drivers/net/ethernet/intel/igb/igb.o
  LD [M]  drivers/net/ethernet/intel/e1000e/e1000e.o
  LD      drivers/net/ethernet/built-in.o
  LD      drivers/net/built-in.o
Makefile:976: recipe for target 'drivers' failed
make: *** [drivers] Error 2

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[PATCH v2] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Chris Wilson]

Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled

"Display flickering may occur when both FBC (Frame Buffer Compression)
and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
and in use by the display controller."

Ville found the w/a name in the database:
WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl

v2: Log when the quirk is applied.
v3: Ensure i915.enable_fbc is false when !HAS_FBC()
v4: Fix function name after rebase

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_fbc.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index 8147eb9e8475..b673c7c54a46 100644
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -1229,12 +1229,28 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
 	if (i915.enable_fbc >= 0)
 		return !!i915.enable_fbc;
 
+	if (!HAS_FBC(dev_priv))
+		return 0;
+
 	if (IS_BROADWELL(dev_priv))
 		return 1;
 
 	return 0;
 }
 
+static bool need_fbc_wa(struct drm_i915_private *dev_priv)
+{
+#ifdef CONFIG_INTEL_IOMMU
+	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl */
+	if (intel_iommu_gfx_mapped && IS_SKYLAKE(dev_priv)) {
+		DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n");
+		return true;
+	}
+#endif
+
+	return false;
+}
+
 /**
  * intel_fbc_init - Initialize FBC
  * @dev_priv: the i915 device
@@ -1252,6 +1268,9 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
 	fbc->active = false;
 	fbc->work.scheduled = false;
 
+	if (need_fbc_wa(dev_priv))
+		mkwrite_device_info(dev_priv)->has_fbc = false;
+
 	i915.enable_fbc = intel_sanitize_fbc_option(dev_priv);
 	DRM_DEBUG_KMS("Sanitized enable_fbc value: %d\n", i915.enable_fbc);
 
-- 
2.8.1

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Re: [PATCH] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1803 bytes --]

Hi Chris,

[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on next-20160803]
[cannot apply to v4.7]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Chris-Wilson/drm-i915-fbc-FBC-causes-display-flicker-when-VT-d-is-enabled-on-Skylake/20160804-001041
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: x86_64-randconfig-x015-201631 (attached as .config)
compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   drivers/gpu/drm/i915/intel_fbc.c: In function 'intel_fbc_init':
>> drivers/gpu/drm/i915/intel_fbc.c:1273:3: error: implicit declaration of function 'mkwrite_intel_info' [-Werror=implicit-function-declaration]
      mkwrite_intel_info(dev_priv)->has_fbc = false;
      ^~~~~~~~~~~~~~~~~~
>> drivers/gpu/drm/i915/intel_fbc.c:1273:31: error: invalid type argument of '->' (have 'int')
      mkwrite_intel_info(dev_priv)->has_fbc = false;
                                  ^~
   cc1: some warnings being treated as errors

vim +/mkwrite_intel_info +1273 drivers/gpu/drm/i915/intel_fbc.c

  1267		mutex_init(&fbc->lock);
  1268		fbc->enabled = false;
  1269		fbc->active = false;
  1270		fbc->work.scheduled = false;
  1271	
  1272		if (need_fbc_wa(dev_priv))
> 1273			mkwrite_intel_info(dev_priv)->has_fbc = false;
  1274	
  1275		i915.enable_fbc = intel_sanitize_fbc_option(dev_priv);
  1276		DRM_DEBUG_KMS("Sanitized enable_fbc value: %d\n", i915.enable_fbc);

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 27321 bytes --]

[-- Attachment #3: Type: text/plain, Size: 160 bytes --]

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✗ Ro.CI.BAT: warning for drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake (rev2)

[Patchwork]

== Series Details ==

Series: drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake (rev2)
URL   : https://patchwork.freedesktop.org/series/10606/
State : warning

== Summary ==

Series 10606v2 drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake
http://patchwork.freedesktop.org/api/1.0/series/10606/revisions/2/mbox

Test drv_module_reload_basic:
                pass       -> SKIP       (ro-hsw-i3-4010u)
                pass       -> SKIP       (fi-skl-i5-6260u)
Test gem_exec_gttfill:
        Subgroup basic:
                skip       -> PASS       (fi-snb-i7-2600)
Test kms_cursor_legacy:
        Subgroup basic-flip-vs-cursor-legacy:
                fail       -> PASS       (ro-hsw-i7-4770r)
        Subgroup basic-flip-vs-cursor-varying-size:
                fail       -> PASS       (ro-skl3-i5-6260u)

fi-hsw-i7-4770k  total:240  pass:218  dwarn:0   dfail:0   fail:0   skip:22 
fi-kbl-qkkr      total:240  pass:182  dwarn:28  dfail:0   fail:3   skip:27 
fi-skl-i5-6260u  total:240  pass:223  dwarn:0   dfail:0   fail:2   skip:15 
fi-skl-i7-6700k  total:240  pass:209  dwarn:0   dfail:0   fail:3   skip:28 
fi-snb-i7-2600   total:240  pass:198  dwarn:0   dfail:0   fail:0   skip:42 
ro-bdw-i5-5250u  total:240  pass:220  dwarn:4   dfail:0   fail:0   skip:16 
ro-bdw-i7-5557U  total:240  pass:224  dwarn:0   dfail:0   fail:0   skip:16 
ro-bdw-i7-5600u  total:240  pass:206  dwarn:0   dfail:0   fail:2   skip:32 
ro-bsw-n3050     total:240  pass:195  dwarn:0   dfail:0   fail:3   skip:42 
ro-byt-n2820     total:240  pass:197  dwarn:0   dfail:0   fail:3   skip:40 
ro-hsw-i3-4010u  total:240  pass:213  dwarn:0   dfail:0   fail:0   skip:27 
ro-hsw-i7-4770r  total:240  pass:214  dwarn:0   dfail:0   fail:0   skip:26 
ro-ilk-i7-620lm  total:240  pass:173  dwarn:1   dfail:0   fail:1   skip:65 
ro-ilk1-i5-650   total:235  pass:173  dwarn:0   dfail:0   fail:2   skip:60 
ro-ivb2-i7-3770  total:240  pass:209  dwarn:0   dfail:0   fail:0   skip:31 
ro-skl3-i5-6260u total:240  pass:223  dwarn:0   dfail:0   fail:3   skip:14 
ro-ivb-i7-3770 failed to connect after reboot
ro-snb-i7-2620M failed to connect after reboot

Results at /archive/results/CI_IGT_test/RO_Patchwork_1686/

4d6f224 drm-intel-nightly: 2016y-08m-03d-15h-38m-31s UTC integration manifest
cb4539a drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

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Re: [PATCH v2] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Jani Nikula]

On Wed, 03 Aug 2016, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled
>
> "Display flickering may occur when both FBC (Frame Buffer Compression)
> and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
> and in use by the display controller."
>
> Ville found the w/a name in the database:
> WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl
>
> v2: Log when the quirk is applied.
> v3: Ensure i915.enable_fbc is false when !HAS_FBC()
> v4: Fix function name after rebase
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>

Cc: stable@vger.kernel.org

?

> ---
>  drivers/gpu/drm/i915/intel_fbc.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
> index 8147eb9e8475..b673c7c54a46 100644
> --- a/drivers/gpu/drm/i915/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/intel_fbc.c
> @@ -1229,12 +1229,28 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
>  	if (i915.enable_fbc >= 0)
>  		return !!i915.enable_fbc;
>  
> +	if (!HAS_FBC(dev_priv))
> +		return 0;
> +
>  	if (IS_BROADWELL(dev_priv))
>  		return 1;
>  
>  	return 0;
>  }
>  
> +static bool need_fbc_wa(struct drm_i915_private *dev_priv)
> +{
> +#ifdef CONFIG_INTEL_IOMMU
> +	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl */
> +	if (intel_iommu_gfx_mapped && IS_SKYLAKE(dev_priv)) {
> +		DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n");
> +		return true;
> +	}
> +#endif
> +
> +	return false;
> +}
> +
>  /**
>   * intel_fbc_init - Initialize FBC
>   * @dev_priv: the i915 device
> @@ -1252,6 +1268,9 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
>  	fbc->active = false;
>  	fbc->work.scheduled = false;
>  
> +	if (need_fbc_wa(dev_priv))
> +		mkwrite_device_info(dev_priv)->has_fbc = false;
> +
>  	i915.enable_fbc = intel_sanitize_fbc_option(dev_priv);
>  	DRM_DEBUG_KMS("Sanitized enable_fbc value: %d\n", i915.enable_fbc);

-- 
Jani Nikula, Intel Open Source Technology Center
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Re: [PATCH v2] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Ville Syrjälä]

On Wed, Aug 03, 2016 at 05:16:42PM +0100, Chris Wilson wrote:
> Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled
> 
> "Display flickering may occur when both FBC (Frame Buffer Compression)
> and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
> and in use by the display controller."
> 
> Ville found the w/a name in the database:
> WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl
> 
> v2: Log when the quirk is applied.
> v3: Ensure i915.enable_fbc is false when !HAS_FBC()
> v4: Fix function name after rebase
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_fbc.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
> index 8147eb9e8475..b673c7c54a46 100644
> --- a/drivers/gpu/drm/i915/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/intel_fbc.c
> @@ -1229,12 +1229,28 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
>  	if (i915.enable_fbc >= 0)
>  		return !!i915.enable_fbc;
>  
> +	if (!HAS_FBC(dev_priv))
> +		return 0;
> +
>  	if (IS_BROADWELL(dev_priv))
>  		return 1;
>  
>  	return 0;
>  }
>  
> +static bool need_fbc_wa(struct drm_i915_private *dev_priv)

need_fbc_vtd_wa() perhaps?

> +{
> +#ifdef CONFIG_INTEL_IOMMU
> +	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl */
> +	if (intel_iommu_gfx_mapped && IS_SKYLAKE(dev_priv)) {

BXT needs this as well AFAICS.

with that added
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> +		DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n");
> +		return true;
> +	}
> +#endif
> +
> +	return false;
> +}
> +
>  /**
>   * intel_fbc_init - Initialize FBC
>   * @dev_priv: the i915 device
> @@ -1252,6 +1268,9 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
>  	fbc->active = false;
>  	fbc->work.scheduled = false;
>  
> +	if (need_fbc_wa(dev_priv))
> +		mkwrite_device_info(dev_priv)->has_fbc = false;
> +
>  	i915.enable_fbc = intel_sanitize_fbc_option(dev_priv);
>  	DRM_DEBUG_KMS("Sanitized enable_fbc value: %d\n", i915.enable_fbc);
>  
> -- 
> 2.8.1

-- 
Ville Syrjälä
Intel OTC
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Re: [PATCH v2] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Chris Wilson]

On Thu, Aug 04, 2016 at 09:57:11AM +0300, Ville Syrjälä wrote:
> On Wed, Aug 03, 2016 at 05:16:42PM +0100, Chris Wilson wrote:
> > Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled
> > 
> > "Display flickering may occur when both FBC (Frame Buffer Compression)
> > and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
> > and in use by the display controller."
> > 
> > Ville found the w/a name in the database:
> > WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl
> > 
> > v2: Log when the quirk is applied.
> > v3: Ensure i915.enable_fbc is false when !HAS_FBC()
> > v4: Fix function name after rebase
> > 
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_fbc.c | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
> > index 8147eb9e8475..b673c7c54a46 100644
> > --- a/drivers/gpu/drm/i915/intel_fbc.c
> > +++ b/drivers/gpu/drm/i915/intel_fbc.c
> > @@ -1229,12 +1229,28 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
> >  	if (i915.enable_fbc >= 0)
> >  		return !!i915.enable_fbc;
> >  
> > +	if (!HAS_FBC(dev_priv))
> > +		return 0;
> > +
> >  	if (IS_BROADWELL(dev_priv))
> >  		return 1;
> >  
> >  	return 0;
> >  }
> >  
> > +static bool need_fbc_wa(struct drm_i915_private *dev_priv)
> 
> need_fbc_vtd_wa() perhaps?

Right now, yes. I left it open just in case - but that's most likely a
false hope.

> > +{
> > +#ifdef CONFIG_INTEL_IOMMU
> > +	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl */
> > +	if (intel_iommu_gfx_mapped && IS_SKYLAKE(dev_priv)) {
> 
> BXT needs this as well AFAICS.

Will IS_GEN9() suit? +skl,bxt in the description.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
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Re: [PATCH v2] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Ville Syrjälä]

On Thu, Aug 04, 2016 at 08:03:09AM +0100, Chris Wilson wrote:
> On Thu, Aug 04, 2016 at 09:57:11AM +0300, Ville Syrjälä wrote:
> > On Wed, Aug 03, 2016 at 05:16:42PM +0100, Chris Wilson wrote:
> > > Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled
> > > 
> > > "Display flickering may occur when both FBC (Frame Buffer Compression)
> > > and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
> > > and in use by the display controller."
> > > 
> > > Ville found the w/a name in the database:
> > > WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl
> > > 
> > > v2: Log when the quirk is applied.
> > > v3: Ensure i915.enable_fbc is false when !HAS_FBC()
> > > v4: Fix function name after rebase
> > > 
> > > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > > Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_fbc.c | 19 +++++++++++++++++++
> > >  1 file changed, 19 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
> > > index 8147eb9e8475..b673c7c54a46 100644
> > > --- a/drivers/gpu/drm/i915/intel_fbc.c
> > > +++ b/drivers/gpu/drm/i915/intel_fbc.c
> > > @@ -1229,12 +1229,28 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
> > >  	if (i915.enable_fbc >= 0)
> > >  		return !!i915.enable_fbc;
> > >  
> > > +	if (!HAS_FBC(dev_priv))
> > > +		return 0;
> > > +
> > >  	if (IS_BROADWELL(dev_priv))
> > >  		return 1;
> > >  
> > >  	return 0;
> > >  }
> > >  
> > > +static bool need_fbc_wa(struct drm_i915_private *dev_priv)
> > 
> > need_fbc_vtd_wa() perhaps?
> 
> Right now, yes. I left it open just in case - but that's most likely a
> false hope.
> 
> > > +{
> > > +#ifdef CONFIG_INTEL_IOMMU
> > > +	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl */
> > > +	if (intel_iommu_gfx_mapped && IS_SKYLAKE(dev_priv)) {
> > 
> > BXT needs this as well AFAICS.
> 
> Will IS_GEN9() suit? +skl,bxt in the description.

Looks like KBL doesn't need this w/a.

-- 
Ville Syrjälä
Intel OTC
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[PATCH v3] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Chris Wilson]

Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled

"Display flickering may occur when both FBC (Frame Buffer Compression)
and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
and in use by the display controller."

Ville found the w/a name in the database:
WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt and also dug out that it
affects Broxton.

v2: Log when the quirk is applied.
v3: Ensure i915.enable_fbc is false when !HAS_FBC()
v4: Fix function name after rebase
v5: Add Broxton to the workaround

Note for backporting to stable, we need to add
	((struct intel_device_info *)INTEL_INFO(ptr))

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/i915/intel_fbc.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index 8147eb9e8475..d4be07615aa9 100644
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -1229,12 +1229,29 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
 	if (i915.enable_fbc >= 0)
 		return !!i915.enable_fbc;
 
+	if (!HAS_FBC(dev_priv))
+		return 0;
+
 	if (IS_BROADWELL(dev_priv))
 		return 1;
 
 	return 0;
 }
 
+static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv)
+{
+#ifdef CONFIG_INTEL_IOMMU
+	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */
+	if (intel_iommu_gfx_mapped &&
+	    (IS_SKYLAKE(dev_priv) || IS_BROXTON(dev_priv))) {
+		DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n");
+		return true;
+	}
+#endif
+
+	return false;
+}
+
 /**
  * intel_fbc_init - Initialize FBC
  * @dev_priv: the i915 device
@@ -1252,6 +1269,9 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
 	fbc->active = false;
 	fbc->work.scheduled = false;
 
+	if (need_fbc_vtd_wa(dev_priv))
+		mkwrite_device_info(dev_priv)->has_fbc = false;
+
 	i915.enable_fbc = intel_sanitize_fbc_option(dev_priv);
 	DRM_DEBUG_KMS("Sanitized enable_fbc value: %d\n", i915.enable_fbc);
 
-- 
2.8.1

✗ Ro.CI.BAT: failure for drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake (rev3)

[Patchwork]

== Series Details ==

Series: drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake (rev3)
URL   : https://patchwork.freedesktop.org/series/10606/
State : failure

== Summary ==

Series 10606v3 drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake
http://patchwork.freedesktop.org/api/1.0/series/10606/revisions/3/mbox

Test kms_cursor_legacy:
        Subgroup basic-flip-vs-cursor-legacy:
                fail       -> PASS       (ro-bdw-i7-5600u)
                fail       -> PASS       (ro-bdw-i5-5250u)
                pass       -> FAIL       (ro-skl3-i5-6260u)

fi-hsw-i7-4770k  total:240  pass:218  dwarn:0   dfail:0   fail:0   skip:22 
fi-kbl-qkkr      total:240  pass:182  dwarn:29  dfail:0   fail:3   skip:26 
fi-skl-i5-6260u  total:240  pass:224  dwarn:0   dfail:0   fail:2   skip:14 
fi-skl-i7-6700k  total:240  pass:208  dwarn:0   dfail:0   fail:4   skip:28 
fi-snb-i7-2600   total:240  pass:198  dwarn:0   dfail:0   fail:0   skip:42 
ro-bdw-i5-5250u  total:240  pass:219  dwarn:4   dfail:0   fail:1   skip:16 
ro-bdw-i7-5557U  total:240  pass:224  dwarn:0   dfail:0   fail:0   skip:16 
ro-bdw-i7-5600u  total:240  pass:207  dwarn:0   dfail:0   fail:1   skip:32 
ro-bsw-n3050     total:240  pass:194  dwarn:0   dfail:0   fail:4   skip:42 
ro-byt-n2820     total:240  pass:197  dwarn:0   dfail:0   fail:3   skip:40 
ro-hsw-i3-4010u  total:240  pass:214  dwarn:0   dfail:0   fail:0   skip:26 
ro-hsw-i7-4770r  total:240  pass:214  dwarn:0   dfail:0   fail:0   skip:26 
ro-ilk-i7-620lm  total:240  pass:173  dwarn:1   dfail:0   fail:1   skip:65 
ro-ilk1-i5-650   total:235  pass:173  dwarn:0   dfail:0   fail:2   skip:60 
ro-ivb-i7-3770   total:240  pass:205  dwarn:0   dfail:0   fail:0   skip:35 
ro-ivb2-i7-3770  total:240  pass:209  dwarn:0   dfail:0   fail:0   skip:31 
ro-skl3-i5-6260u total:240  pass:222  dwarn:0   dfail:0   fail:4   skip:14 
ro-snb-i7-2620M  total:240  pass:198  dwarn:0   dfail:0   fail:1   skip:41 

Results at /archive/results/CI_IGT_test/RO_Patchwork_1700/

4a66cc6 drm-intel-nightly: 2016y-08m-04d-08h-20m-44s UTC integration manifest
a02d00e drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

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Re: [PATCH v2] drm/i915/fbc: FBC causes display flicker when VT-d is enabled on Skylake

[Daniel Vetter]

On Thu, Aug 04, 2016 at 09:31:20AM +0300, Jani Nikula wrote:
> On Wed, 03 Aug 2016, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> > Erratum SKL075: Display Flicker May Occur When Both VT-d And FBC Are Enabled
> >
> > "Display flickering may occur when both FBC (Frame Buffer Compression)
> > and VT - d (Intel® Virtualization Technology for Directed I/O) are enabled
> > and in use by the display controller."
> >
> > Ville found the w/a name in the database:
> > WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl
> >
> > v2: Log when the quirk is applied.
> > v3: Ensure i915.enable_fbc is false when !HAS_FBC()
> > v4: Fix function name after rebase
> >
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Cc: stable@vger.kernel.org

fbc isn't enabled by default, so imo no.
-Daniel

> 
> ?
> 
> > ---
> >  drivers/gpu/drm/i915/intel_fbc.c | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
> > index 8147eb9e8475..b673c7c54a46 100644
> > --- a/drivers/gpu/drm/i915/intel_fbc.c
> > +++ b/drivers/gpu/drm/i915/intel_fbc.c
> > @@ -1229,12 +1229,28 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
> >  	if (i915.enable_fbc >= 0)
> >  		return !!i915.enable_fbc;
> >  
> > +	if (!HAS_FBC(dev_priv))
> > +		return 0;
> > +
> >  	if (IS_BROADWELL(dev_priv))
> >  		return 1;
> >  
> >  	return 0;
> >  }
> >  
> > +static bool need_fbc_wa(struct drm_i915_private *dev_priv)
> > +{
> > +#ifdef CONFIG_INTEL_IOMMU
> > +	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl */
> > +	if (intel_iommu_gfx_mapped && IS_SKYLAKE(dev_priv)) {
> > +		DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n");
> > +		return true;
> > +	}
> > +#endif
> > +
> > +	return false;
> > +}
> > +
> >  /**
> >   * intel_fbc_init - Initialize FBC
> >   * @dev_priv: the i915 device
> > @@ -1252,6 +1268,9 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
> >  	fbc->active = false;
> >  	fbc->work.scheduled = false;
> >  
> > +	if (need_fbc_wa(dev_priv))
> > +		mkwrite_device_info(dev_priv)->has_fbc = false;
> > +
> >  	i915.enable_fbc = intel_sanitize_fbc_option(dev_priv);
> >  	DRM_DEBUG_KMS("Sanitized enable_fbc value: %d\n", i915.enable_fbc);
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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