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Groups > linux.kernel > #1460766 > unrolled thread

[PATCH v11 1/7] drm/i915/gen6+: Return -EINVAL on invalid pcode commands

Started byLyude <cpaul@redhat.com>
First post2016-08-11 22:00 +0200
Last post2016-08-12 13:30 +0200
Articles 2 — 2 participants

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  [PATCH v11 1/7] drm/i915/gen6+: Return -EINVAL on invalid pcode commands Lyude <cpaul@redhat.com> - 2016-08-11 22:00 +0200
    Re: [PATCH v11 1/7] drm/i915/gen6+: Return -EINVAL on invalid pcode  commands Ville Syrjälä <ville.syrjala@linux.intel.com> - 2016-08-12 13:30 +0200

#1460766 — [PATCH v11 1/7] drm/i915/gen6+: Return -EINVAL on invalid pcode commands

FromLyude <cpaul@redhat.com>
Date2016-08-11 22:00 +0200
Subject[PATCH v11 1/7] drm/i915/gen6+: Return -EINVAL on invalid pcode commands
Message-ID<s54j0-8i5-25@gated-at.bofh.it>
In order to add proper support for the SAGV, we need to be able to know
what the cause of a failure to change the SAGV through the pcode mailbox
was. The reasoning for this is that some very early pre-release Skylake
machines don't actually allow you to control the SAGV on them, and
indicate an invalid mailbox command was sent.

This also might come in handy in the future for debugging.

Signed-off-by: Lyude <cpaul@redhat.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/i915/i915_reg.h |  1 +
 drivers/gpu/drm/i915/intel_pm.c | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index da82744..73b3d4d 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7121,6 +7121,7 @@ enum {
 #define VLV_MEDIA_C0_COUNT			_MMIO(0x13811C)
 
 #define GEN6_PCODE_MAILBOX			_MMIO(0x138124)
+#define   GEN6_PCODE_INVALID_CMD		(1<<0)
 #define   GEN6_PCODE_READY			(1<<31)
 #define	  GEN6_PCODE_WRITE_RC6VIDS		0x4
 #define	  GEN6_PCODE_READ_RC6VIDS		0x5
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 99014d7..8752730 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -7674,6 +7674,11 @@ int sandybridge_pcode_read(struct drm_i915_private *dev_priv, u32 mbox, u32 *val
 	*val = I915_READ_FW(GEN6_PCODE_DATA);
 	I915_WRITE_FW(GEN6_PCODE_DATA, 0);
 
+	if (I915_READ_FW(GEN6_PCODE_MAILBOX) & GEN6_PCODE_INVALID_CMD) {
+		DRM_DEBUG_DRIVER("warning: pcode (read) mailbox access indicated invalid command\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -7704,6 +7709,11 @@ int sandybridge_pcode_write(struct drm_i915_private *dev_priv,
 
 	I915_WRITE_FW(GEN6_PCODE_DATA, 0);
 
+	if (I915_READ_FW(GEN6_PCODE_MAILBOX) & GEN6_PCODE_INVALID_CMD) {
+		DRM_DEBUG_DRIVER("warning: pcode (write) mailbox access indicated invalid command\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
-- 
2.7.4

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#1461107 — Re: [PATCH v11 1/7] drm/i915/gen6+: Return -EINVAL on invalid pcode commands

FromVille Syrjälä <ville.syrjala@linux.intel.com>
Date2016-08-12 13:30 +0200
SubjectRe: [PATCH v11 1/7] drm/i915/gen6+: Return -EINVAL on invalid pcode commands
Message-ID<s5iP0-Yf-43@gated-at.bofh.it>
In reply to#1460766
On Thu, Aug 11, 2016 at 03:54:30PM -0400, Lyude wrote:
> In order to add proper support for the SAGV, we need to be able to know
> what the cause of a failure to change the SAGV through the pcode mailbox
> was. The reasoning for this is that some very early pre-release Skylake
> machines don't actually allow you to control the SAGV on them, and
> indicate an invalid mailbox command was sent.
> 
> This also might come in handy in the future for debugging.
> 
> Signed-off-by: Lyude <cpaul@redhat.com>
> Cc: Matt Roper <matthew.d.roper@intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/gpu/drm/i915/i915_reg.h |  1 +
>  drivers/gpu/drm/i915/intel_pm.c | 10 ++++++++++
>  2 files changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index da82744..73b3d4d 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -7121,6 +7121,7 @@ enum {
>  #define VLV_MEDIA_C0_COUNT			_MMIO(0x13811C)
>  
>  #define GEN6_PCODE_MAILBOX			_MMIO(0x138124)
> +#define   GEN6_PCODE_INVALID_CMD		(1<<0)

It doesn't work quite like that. Instead the low 8 bits will contian
the error code, iff pcode has cleared the "READY" bit:

snb-ivb docs say:
00h MAILBOX_GTDRIVER_CC_SUCCESS
01h MAILBOX_GTDRIVER_CC_ILLEGAL_CMD
02h MAILBOX_GTDRIVER_CC_MIN_FREQUENCY_TABLE_GT_RATIO_OUT_OF_RANGE
03h MAILBOX_GTDRIVER_CC_TIMEOUT
FFh MAILBOX_GTDRIVER_CC_UNIMPLEMENTED_CMD

hsw-bdw docs say:
00h SUCCESS
01h ILLEGAL_CMD
02h TIMEOUT
03h ILLEGAL_DATA
10h MIN_FREQUENCY_TABLE_GT_RATIO_OUT_OF_RANGE

skl docs say:
00h SUCCESS
01h ILLEGAL_CMD
02h TIMEOUT
03h ILLEGAL_DATA

So looks like 02h and 03h will need to be interpreted in two different
ways depending on the platform. Assuming we want to decode the error
into a a human readable form for dmesg.

>  #define   GEN6_PCODE_READY			(1<<31)
>  #define	  GEN6_PCODE_WRITE_RC6VIDS		0x4
>  #define	  GEN6_PCODE_READ_RC6VIDS		0x5
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 99014d7..8752730 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -7674,6 +7674,11 @@ int sandybridge_pcode_read(struct drm_i915_private *dev_priv, u32 mbox, u32 *val
>  	*val = I915_READ_FW(GEN6_PCODE_DATA);
>  	I915_WRITE_FW(GEN6_PCODE_DATA, 0);
>  
> +	if (I915_READ_FW(GEN6_PCODE_MAILBOX) & GEN6_PCODE_INVALID_CMD) {
> +		DRM_DEBUG_DRIVER("warning: pcode (read) mailbox access indicated invalid command\n");
> +		return -EINVAL;
> +	}
> +
>  	return 0;
>  }
>  
> @@ -7704,6 +7709,11 @@ int sandybridge_pcode_write(struct drm_i915_private *dev_priv,
>  
>  	I915_WRITE_FW(GEN6_PCODE_DATA, 0);
>  
> +	if (I915_READ_FW(GEN6_PCODE_MAILBOX) & GEN6_PCODE_INVALID_CMD) {
> +		DRM_DEBUG_DRIVER("warning: pcode (write) mailbox access indicated invalid command\n");
> +		return -EINVAL;
> +	}
> +
>  	return 0;
>  }
>  
> -- 
> 2.7.4

-- 
Ville Syrjälä
Intel OTC

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