diff mbox

[1/2,v2,addendum] drm/i915: Allow parsing of variable size child device entries from VBT

Message ID 20150812102917.GL6150@boom (mailing list archive)
State New, archived
Headers show

Commit Message

David Weinehall Aug. 12, 2015, 10:29 a.m. UTC
Some more fixup is needed; the bits from Antti's patch
that actually expanded the struct to fully fit the newer
versions of the child_device_config was part of the second
patch; since that patch hasn't been merged yet we need this bit:

This applies on top of the patch you already merged
(the Iboost patch will need corresponding adjustment to
 remove the changes I split out):

Expand common_child_dev_config to be able to fit all information
defined by the latest VBT specification.

Signed-off-by: David Weinehall <david.weinehall@linux.intel.com>
CC: Antti Koskipaa <antti.koskipaa@linux.intel.com>
---
 intel_bios.c |    7 ++++++-
 intel_bios.h |    4 ++++
 2 files changed, 10 insertions(+), 1 deletion(-)

Comments

Jani Nikula Aug. 12, 2015, 12:13 p.m. UTC | #1
On Wed, 12 Aug 2015, David Weinehall <david.weinehall@linux.intel.com> wrote:
> Some more fixup is needed; the bits from Antti's patch
> that actually expanded the struct to fully fit the newer
> versions of the child_device_config was part of the second
> patch; since that patch hasn't been merged yet we need this bit:
>
> This applies on top of the patch you already merged
> (the Iboost patch will need corresponding adjustment to
>  remove the changes I split out):
>
> Expand common_child_dev_config to be able to fit all information
> defined by the latest VBT specification.
>
> Signed-off-by: David Weinehall <david.weinehall@linux.intel.com>
> CC: Antti Koskipaa <antti.koskipaa@linux.intel.com>
> ---
>  intel_bios.c |    7 ++++++-
>  intel_bios.h |    4 ++++
>  2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> index 990acc20771a..40e2cc4e7419 100644
> --- a/drivers/gpu/drm/i915/intel_bios.c
> +++ b/drivers/gpu/drm/i915/intel_bios.c
> @@ -1038,6 +1038,10 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
>  		DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
>  		return;
>  	}
> +	/* Remember to keep this in sync with child_device_config;
> +	 * whenever a new feature is added to BDB that causes that
> +	 * struct to grow this needs to be updated too
> +	 */

BUILD_BUG_ON(something about sizeof child device config) ?

>  	if (bdb->version < 195) {
>  		expected_size = 33;
>  	} else if (bdb->version == 195) {
> @@ -1051,7 +1055,8 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
>  	}
>  
>  	if (expected_size > sizeof(*p_child)) {
> -		DRM_ERROR("child_device_config cannot fit in p_child\n");
> +		DRM_ERROR("child_device_config (size %u) cannot fit in p_child (size %u); bdb->version: %u\n",
> +			  expected_size, sizeof(*p_child), bdb->version);
>  		return;
>  	}
>  
> diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
> index f7ad6a585129..71cb96f77870 100644
> --- a/drivers/gpu/drm/i915/intel_bios.h
> +++ b/drivers/gpu/drm/i915/intel_bios.h
> @@ -239,6 +239,10 @@ struct common_child_dev_config {
>  	u8 not_common2[2];
>  	u8 ddc_pin;
>  	u16 edid_ptr;
> +	u8 obsolete;
> +	u8 flags_1;
> +	u8 not_common3[13];
> +	u8 iboost_level;
>  } __packed;
>  
>  /* This field changes depending on the BDB version, so the most reliable way to
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
Jani Nikula Aug. 12, 2015, 2:19 p.m. UTC | #2
On Wed, 12 Aug 2015, David Weinehall <david.weinehall@linux.intel.com> wrote:
> Some more fixup is needed; the bits from Antti's patch
> that actually expanded the struct to fully fit the newer
> versions of the child_device_config was part of the second
> patch; since that patch hasn't been merged yet we need this bit:
>
> This applies on top of the patch you already merged
> (the Iboost patch will need corresponding adjustment to
>  remove the changes I split out):
>
> Expand common_child_dev_config to be able to fit all information
> defined by the latest VBT specification.
>
> Signed-off-by: David Weinehall <david.weinehall@linux.intel.com>
> CC: Antti Koskipaa <antti.koskipaa@linux.intel.com>
> ---
>  intel_bios.c |    7 ++++++-
>  intel_bios.h |    4 ++++
>  2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> index 990acc20771a..40e2cc4e7419 100644
> --- a/drivers/gpu/drm/i915/intel_bios.c
> +++ b/drivers/gpu/drm/i915/intel_bios.c
> @@ -1038,6 +1038,10 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
>  		DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
>  		return;
>  	}
> +	/* Remember to keep this in sync with child_device_config;
> +	 * whenever a new feature is added to BDB that causes that
> +	 * struct to grow this needs to be updated too
> +	 */
>  	if (bdb->version < 195) {
>  		expected_size = 33;
>  	} else if (bdb->version == 195) {
> @@ -1051,7 +1055,8 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
>  	}
>  
>  	if (expected_size > sizeof(*p_child)) {
> -		DRM_ERROR("child_device_config cannot fit in p_child\n");
> +		DRM_ERROR("child_device_config (size %u) cannot fit in p_child (size %u); bdb->version: %u\n",
> +			  expected_size, sizeof(*p_child), bdb->version);

drivers/gpu/drm/i915/intel_bios.c: In function ‘parse_device_mapping’:
drivers/gpu/drm/i915/intel_bios.c:1058:3: warning: format ‘%u’ expects argument of type ‘unsigned int’, but argument 3 has type ‘long unsigned int’ [-Wformat=]
   DRM_ERROR("child_device_config (size %u) cannot fit in p_child (size %u); bdb->version: %u\n",
   ^
  CC [M]  drivers/gpu/drm/i915/intel_fifo_underrun.o


>  		return;
>  	}
>  
> diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
> index f7ad6a585129..71cb96f77870 100644
> --- a/drivers/gpu/drm/i915/intel_bios.h
> +++ b/drivers/gpu/drm/i915/intel_bios.h
> @@ -239,6 +239,10 @@ struct common_child_dev_config {
>  	u8 not_common2[2];
>  	u8 ddc_pin;
>  	u16 edid_ptr;
> +	u8 obsolete;
> +	u8 flags_1;
> +	u8 not_common3[13];
> +	u8 iboost_level;
>  } __packed;
>  
>  /* This field changes depending on the BDB version, so the most reliable way to
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
David Weinehall Aug. 13, 2015, 10:30 a.m. UTC | #3
On Wed, Aug 12, 2015 at 03:13:35PM +0300, Jani Nikula wrote:
> On Wed, 12 Aug 2015, David Weinehall <david.weinehall@linux.intel.com> wrote:
> > Some more fixup is needed; the bits from Antti's patch
> > that actually expanded the struct to fully fit the newer
> > versions of the child_device_config was part of the second
> > patch; since that patch hasn't been merged yet we need this bit:
> >
> > This applies on top of the patch you already merged
> > (the Iboost patch will need corresponding adjustment to
> >  remove the changes I split out):
> >
> > Expand common_child_dev_config to be able to fit all information
> > defined by the latest VBT specification.
> >
> > Signed-off-by: David Weinehall <david.weinehall@linux.intel.com>
> > CC: Antti Koskipaa <antti.koskipaa@linux.intel.com>
> > ---
> >  intel_bios.c |    7 ++++++-
> >  intel_bios.h |    4 ++++
> >  2 files changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> > index 990acc20771a..40e2cc4e7419 100644
> > --- a/drivers/gpu/drm/i915/intel_bios.c
> > +++ b/drivers/gpu/drm/i915/intel_bios.c
> > @@ -1038,6 +1038,10 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
> >  		DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
> >  		return;
> >  	}
> > +	/* Remember to keep this in sync with child_device_config;
> > +	 * whenever a new feature is added to BDB that causes that
> > +	 * struct to grow this needs to be updated too
> > +	 */
> 
> BUILD_BUG_ON(something about sizeof child device config) ?

The idea is nice, but...  We get the size to copy (expected_size)
from the version-switch statement (so it's not available during build);
thus we cannot know at compile time whether expected_size is larger than
sizeof(child_device_config).

This is yet another argument in favour of a version:feature
table I think; that would allow for compile-time validation.

Unless someone else volunteers to refactor this code I can dig in once
I get back from vacation.


Kind regards, David
Jani Nikula Aug. 13, 2015, 11:35 a.m. UTC | #4
On Thu, 13 Aug 2015, David Weinehall <david.weinehall@linux.intel.com> wrote:
> On Wed, Aug 12, 2015 at 03:13:35PM +0300, Jani Nikula wrote:
>> On Wed, 12 Aug 2015, David Weinehall <david.weinehall@linux.intel.com> wrote:
>> > Some more fixup is needed; the bits from Antti's patch
>> > that actually expanded the struct to fully fit the newer
>> > versions of the child_device_config was part of the second
>> > patch; since that patch hasn't been merged yet we need this bit:
>> >
>> > This applies on top of the patch you already merged
>> > (the Iboost patch will need corresponding adjustment to
>> >  remove the changes I split out):
>> >
>> > Expand common_child_dev_config to be able to fit all information
>> > defined by the latest VBT specification.
>> >
>> > Signed-off-by: David Weinehall <david.weinehall@linux.intel.com>
>> > CC: Antti Koskipaa <antti.koskipaa@linux.intel.com>
>> > ---
>> >  intel_bios.c |    7 ++++++-
>> >  intel_bios.h |    4 ++++
>> >  2 files changed, 10 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
>> > index 990acc20771a..40e2cc4e7419 100644
>> > --- a/drivers/gpu/drm/i915/intel_bios.c
>> > +++ b/drivers/gpu/drm/i915/intel_bios.c
>> > @@ -1038,6 +1038,10 @@ parse_device_mapping(struct drm_i915_private *dev_priv,
>> >  		DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
>> >  		return;
>> >  	}
>> > +	/* Remember to keep this in sync with child_device_config;
>> > +	 * whenever a new feature is added to BDB that causes that
>> > +	 * struct to grow this needs to be updated too
>> > +	 */
>> 
>> BUILD_BUG_ON(something about sizeof child device config) ?
>
> The idea is nice, but...  We get the size to copy (expected_size)
> from the version-switch statement (so it's not available during build);
> thus we cannot know at compile time whether expected_size is larger than
> sizeof(child_device_config).
>
> This is yet another argument in favour of a version:feature
> table I think; that would allow for compile-time validation.
>
> Unless someone else volunteers to refactor this code I can dig in once
> I get back from vacation.

Right. To be clear, my question should not block this from being merged.

BR,
Jani

>
>
> Kind regards, David
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
index 990acc20771a..40e2cc4e7419 100644
--- a/drivers/gpu/drm/i915/intel_bios.c
+++ b/drivers/gpu/drm/i915/intel_bios.c
@@ -1038,6 +1038,10 @@  parse_device_mapping(struct drm_i915_private *dev_priv,
 		DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
 		return;
 	}
+	/* Remember to keep this in sync with child_device_config;
+	 * whenever a new feature is added to BDB that causes that
+	 * struct to grow this needs to be updated too
+	 */
 	if (bdb->version < 195) {
 		expected_size = 33;
 	} else if (bdb->version == 195) {
@@ -1051,7 +1055,8 @@  parse_device_mapping(struct drm_i915_private *dev_priv,
 	}
 
 	if (expected_size > sizeof(*p_child)) {
-		DRM_ERROR("child_device_config cannot fit in p_child\n");
+		DRM_ERROR("child_device_config (size %u) cannot fit in p_child (size %u); bdb->version: %u\n",
+			  expected_size, sizeof(*p_child), bdb->version);
 		return;
 	}
 
diff --git a/drivers/gpu/drm/i915/intel_bios.h b/drivers/gpu/drm/i915/intel_bios.h
index f7ad6a585129..71cb96f77870 100644
--- a/drivers/gpu/drm/i915/intel_bios.h
+++ b/drivers/gpu/drm/i915/intel_bios.h
@@ -239,6 +239,10 @@  struct common_child_dev_config {
 	u8 not_common2[2];
 	u8 ddc_pin;
 	u16 edid_ptr;
+	u8 obsolete;
+	u8 flags_1;
+	u8 not_common3[13];
+	u8 iboost_level;
 } __packed;
 
 /* This field changes depending on the BDB version, so the most reliable way to