[PATCH] drm/edid: Extract SADs properly from multiple audio data blocks

[Daniel Vetter]

On Fri, Mar 11, 2016 at 04:24:35PM +0200, Jani Nikula wrote:
> On Fri, 11 Mar 2016, Ville Syrjälä  wrote:
> > [ text/plain ]
> > On Fri, Mar 11, 2016 at 03:36:48PM +0200, Jani Nikula wrote:
> >> On Wed, 09 Mar 2016, ville.syrjala at linux.intel.com wrote:
> >> > From: Ville Syrjälä 
> >> >
> >> > SADs may span multiple CEA audio data blocks in the EDID.
> >> >
> >> > CEA-861-E says:
> >> > "The order of the Data Blocks is not constrained. It is also possible
> >> > to have more than one of a specific type of data block if necessary to
> >> > include all of the descriptors needed to describe the sink’s 
> >> > capabilities."
> >> >
> >> > Each audio data block can carry up to 10 SADs, whereas the ELD SAD limit
> >> > is 15 according to HDA 1.0a spec. So we should support at least two data
> >> > blocks. And apparently some devices take a more liberal interpretation
> >> > and stuff only one SAD per data block even when they would fit into one.
> >> >
> >> > So let's try to extract all the SADs we can fit into the ELD even when
> >> > they span multiple data blocks.
> >> >
> >> > While at it, toss in a comment to explain the 13 byte monitor name
> >> > string limit which confused me at first.
> >> >
> >> > Cc: Arturo Pérez 
> >> > Tested-by: Arturo Pérez 
> >> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94197
> >> > Signed-off-by: Ville Syrjälä 
> >> > ---
> >> >  drivers/gpu/drm/drm_edid.c | 17 +++--
> >> >  1 file changed, 11 insertions(+), 6 deletions(-)
> >> >
> >> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> >> > index fdb1eb014586..414d7f61aa05 100644
> >> > --- a/drivers/gpu/drm/drm_edid.c
> >> > +++ b/drivers/gpu/drm/drm_edid.c
> >> > @@ -3308,7 +3308,7 @@ void drm_edid_to_eld(struct drm_connector 
> >> > *connector, struct edid *edid)
> >> >  u8 *cea;
> >> >  u8 *name;
> >> >  u8 *db;
> >> > -int sad_count = 0;
> >> > +int total_sad_count = 0;
> >> >  int mnl;
> >> >  int dbl;
> >> >  
> >> > @@ -3322,6 +3322,7 @@ void drm_edid_to_eld(struct drm_connector 
> >> > *connector, struct edid *edid)
> >> >  
> >> >  name = NULL;
> >> >  drm_for_each_detailed_block((u8 *)edid, monitor_name, );
> >> > +/* max: 13 bytes EDID, 16 bytes ELD */
> >> >  for (mnl = 0; name && mnl < 13; mnl++) {
> >> >  if (name[mnl] == 0x0a)
> >> >  break;
> >> > @@ -3350,11 +3351,15 @@ void drm_edid_to_eld(struct drm_connector 
> >> > *connector, struct edid *edid)
> >> >  dbl = cea_db_payload_len(db);
> >> >  
> >> >  switch (cea_db_tag(db)) {
> >> > +int sad_count;
> >> > +
> >> >  case AUDIO_BLOCK:
> >> >  /* Audio Data Block, contains SADs */
> >> > -sad_count = dbl / 3;
> >> > -if (dbl >= 1)
> >> > -memcpy(eld + 20 + mnl, [1], 
> >> > dbl);
> >> > +sad_count = min(dbl / 3, 15 - 
> >> > total_sad_count);
> >> 
> >> What if total_sad_count > 15? At a glance, this seems to self correct by
> >> subtracting the excess every second time... ;)
> >
> > Since sad_count will not exceed 15-total_sad_count, total_sad_count will 
> > never
> > exceed 15.
> 
> Right. I guess it could be spelled out for folks like me. :/
> 
> Reviewed-by: Jani Nikula 
> 
> If you run out of things to do (that'll be the day), you could follow up
> with replacing some of the magic here for offsets etc. with the
> DRM_ELD_* defines I added in drm_edid.h.

Applied to drm-misc but not yet pushed since I want to roll forward to
latest drm-next as soon as Dave has merged everything.
-Daniel

> 
> BR,
> Jani.
> 
> 
> >
> >> 
> >> BR,
> >> Jani.
> >> 
> >> > +if (sad_count >= 1)
> >> > +memcpy(eld + 20 + mnl + 
> >> > total_sad_count * 3,
> >> > +   [1], sad_count * 3);
> >> > +total_sad_count += sad_count;
> >> >  break;
> >> >  case SPEAKER_BLOCK:
> >> >  /* Speaker Allocation Data Block */
> >> > @@ -3371,13 +3376,13 @@ void drm_edid_to_eld(struct drm_connector 
> >> > *connector, struct edid *edid)
> >> >  }
> >> >  }
> >> >  }
> >> > -eld[5] |= sad_count << 4;
> >> > +eld[5] |= total_sad_count << 4;
> >> >  
> >> >  eld[DRM_ELD_BASELINE_ELD_LEN] =
> >> >  DIV_ROUND_UP(drm_eld_calc_baseline_block_size(eld), 4);
> >> >  
> >> >  DRM_DEBUG_KMS("ELD size %d, SAD count %d\n",
> >> > -  drm_eld_size(eld), sad_count);
> >> > +  drm_eld_size(eld), 

[PATCH] drm/edid: Extract SADs properly from multiple audio data blocks

[Jani Nikula]

On Fri, 11 Mar 2016, Ville Syrjälä  wrote:
> [ text/plain ]
> On Fri, Mar 11, 2016 at 03:36:48PM +0200, Jani Nikula wrote:
>> On Wed, 09 Mar 2016, ville.syrjala at linux.intel.com wrote:
>> > From: Ville Syrjälä 
>> >
>> > SADs may span multiple CEA audio data blocks in the EDID.
>> >
>> > CEA-861-E says:
>> > "The order of the Data Blocks is not constrained. It is also possible
>> > to have more than one of a specific type of data block if necessary to
>> > include all of the descriptors needed to describe the sink’s 
>> > capabilities."
>> >
>> > Each audio data block can carry up to 10 SADs, whereas the ELD SAD limit
>> > is 15 according to HDA 1.0a spec. So we should support at least two data
>> > blocks. And apparently some devices take a more liberal interpretation
>> > and stuff only one SAD per data block even when they would fit into one.
>> >
>> > So let's try to extract all the SADs we can fit into the ELD even when
>> > they span multiple data blocks.
>> >
>> > While at it, toss in a comment to explain the 13 byte monitor name
>> > string limit which confused me at first.
>> >
>> > Cc: Arturo Pérez 
>> > Tested-by: Arturo Pérez 
>> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94197
>> > Signed-off-by: Ville Syrjälä 
>> > ---
>> >  drivers/gpu/drm/drm_edid.c | 17 +++--
>> >  1 file changed, 11 insertions(+), 6 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> > index fdb1eb014586..414d7f61aa05 100644
>> > --- a/drivers/gpu/drm/drm_edid.c
>> > +++ b/drivers/gpu/drm/drm_edid.c
>> > @@ -3308,7 +3308,7 @@ void drm_edid_to_eld(struct drm_connector 
>> > *connector, struct edid *edid)
>> >u8 *cea;
>> >u8 *name;
>> >u8 *db;
>> > -  int sad_count = 0;
>> > +  int total_sad_count = 0;
>> >int mnl;
>> >int dbl;
>> >  
>> > @@ -3322,6 +3322,7 @@ void drm_edid_to_eld(struct drm_connector 
>> > *connector, struct edid *edid)
>> >  
>> >name = NULL;
>> >drm_for_each_detailed_block((u8 *)edid, monitor_name, );
>> > +  /* max: 13 bytes EDID, 16 bytes ELD */
>> >for (mnl = 0; name && mnl < 13; mnl++) {
>> >if (name[mnl] == 0x0a)
>> >break;
>> > @@ -3350,11 +3351,15 @@ void drm_edid_to_eld(struct drm_connector 
>> > *connector, struct edid *edid)
>> >dbl = cea_db_payload_len(db);
>> >  
>> >switch (cea_db_tag(db)) {
>> > +  int sad_count;
>> > +
>> >case AUDIO_BLOCK:
>> >/* Audio Data Block, contains SADs */
>> > -  sad_count = dbl / 3;
>> > -  if (dbl >= 1)
>> > -  memcpy(eld + 20 + mnl, [1], dbl);
>> > +  sad_count = min(dbl / 3, 15 - total_sad_count);
>> 
>> What if total_sad_count > 15? At a glance, this seems to self correct by
>> subtracting the excess every second time... ;)
>
> Since sad_count will not exceed 15-total_sad_count, total_sad_count will never
> exceed 15.

Right. I guess it could be spelled out for folks like me. :/

Reviewed-by: Jani Nikula 

If you run out of things to do (that'll be the day), you could follow up
with replacing some of the magic here for offsets etc. with the
DRM_ELD_* defines I added in drm_edid.h.

BR,
Jani.


>
>> 
>> BR,
>> Jani.
>> 
>> > +  if (sad_count >= 1)
>> > +  memcpy(eld + 20 + mnl + total_sad_count 
>> > * 3,
>> > + [1], sad_count * 3);
>> > +  total_sad_count += sad_count;
>> >break;
>> >case SPEAKER_BLOCK:
>> >/* Speaker Allocation Data Block */
>> > @@ -3371,13 +3376,13 @@ void drm_edid_to_eld(struct drm_connector 
>> > *connector, struct edid *edid)
>> >}
>> >}
>> >}
>> > -  eld[5] |= sad_count << 4;
>> > +  eld[5] |= total_sad_count << 4;
>> >  
>> >eld[DRM_ELD_BASELINE_ELD_LEN] =
>> >DIV_ROUND_UP(drm_eld_calc_baseline_block_size(eld), 4);
>> >  
>> >DRM_DEBUG_KMS("ELD size %d, SAD count %d\n",
>> > -drm_eld_size(eld), sad_count);
>> > +drm_eld_size(eld), total_sad_count);
>> >  }
>> >  EXPORT_SYMBOL(drm_edid_to_eld);
>> 
>> -- 
>> Jani Nikula, Intel Open Source Technology Center

-- 
Jani Nikula, Intel Open Source Technology Center

[PATCH] drm/edid: Extract SADs properly from multiple audio data blocks

[Ville Syrjälä]

On Fri, Mar 11, 2016 at 03:36:48PM +0200, Jani Nikula wrote:
> On Wed, 09 Mar 2016, ville.syrjala at linux.intel.com wrote:
> > From: Ville Syrjälä 
> >
> > SADs may span multiple CEA audio data blocks in the EDID.
> >
> > CEA-861-E says:
> > "The order of the Data Blocks is not constrained. It is also possible
> > to have more than one of a specific type of data block if necessary to
> > include all of the descriptors needed to describe the sink’s 
> > capabilities."
> >
> > Each audio data block can carry up to 10 SADs, whereas the ELD SAD limit
> > is 15 according to HDA 1.0a spec. So we should support at least two data
> > blocks. And apparently some devices take a more liberal interpretation
> > and stuff only one SAD per data block even when they would fit into one.
> >
> > So let's try to extract all the SADs we can fit into the ELD even when
> > they span multiple data blocks.
> >
> > While at it, toss in a comment to explain the 13 byte monitor name
> > string limit which confused me at first.
> >
> > Cc: Arturo Pérez 
> > Tested-by: Arturo Pérez 
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94197
> > Signed-off-by: Ville Syrjälä 
> > ---
> >  drivers/gpu/drm/drm_edid.c | 17 +++--
> >  1 file changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> > index fdb1eb014586..414d7f61aa05 100644
> > --- a/drivers/gpu/drm/drm_edid.c
> > +++ b/drivers/gpu/drm/drm_edid.c
> > @@ -3308,7 +3308,7 @@ void drm_edid_to_eld(struct drm_connector *connector, 
> > struct edid *edid)
> > u8 *cea;
> > u8 *name;
> > u8 *db;
> > -   int sad_count = 0;
> > +   int total_sad_count = 0;
> > int mnl;
> > int dbl;
> >  
> > @@ -3322,6 +3322,7 @@ void drm_edid_to_eld(struct drm_connector *connector, 
> > struct edid *edid)
> >  
> > name = NULL;
> > drm_for_each_detailed_block((u8 *)edid, monitor_name, );
> > +   /* max: 13 bytes EDID, 16 bytes ELD */
> > for (mnl = 0; name && mnl < 13; mnl++) {
> > if (name[mnl] == 0x0a)
> > break;
> > @@ -3350,11 +3351,15 @@ void drm_edid_to_eld(struct drm_connector 
> > *connector, struct edid *edid)
> > dbl = cea_db_payload_len(db);
> >  
> > switch (cea_db_tag(db)) {
> > +   int sad_count;
> > +
> > case AUDIO_BLOCK:
> > /* Audio Data Block, contains SADs */
> > -   sad_count = dbl / 3;
> > -   if (dbl >= 1)
> > -   memcpy(eld + 20 + mnl, [1], dbl);
> > +   sad_count = min(dbl / 3, 15 - total_sad_count);
> 
> What if total_sad_count > 15? At a glance, this seems to self correct by
> subtracting the excess every second time... ;)

Since sad_count will not exceed 15-total_sad_count, total_sad_count will never
exceed 15.

> 
> BR,
> Jani.
> 
> > +   if (sad_count >= 1)
> > +   memcpy(eld + 20 + mnl + total_sad_count 
> > * 3,
> > +  [1], sad_count * 3);
> > +   total_sad_count += sad_count;
> > break;
> > case SPEAKER_BLOCK:
> > /* Speaker Allocation Data Block */
> > @@ -3371,13 +3376,13 @@ void drm_edid_to_eld(struct drm_connector 
> > *connector, struct edid *edid)
> > }
> > }
> > }
> > -   eld[5] |= sad_count << 4;
> > +   eld[5] |= total_sad_count << 4;
> >  
> > eld[DRM_ELD_BASELINE_ELD_LEN] =
> > DIV_ROUND_UP(drm_eld_calc_baseline_block_size(eld), 4);
> >  
> > DRM_DEBUG_KMS("ELD size %d, SAD count %d\n",
> > - drm_eld_size(eld), sad_count);
> > + drm_eld_size(eld), total_sad_count);
> >  }
> >  EXPORT_SYMBOL(drm_edid_to_eld);
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center

-- 
Ville Syrjälä
Intel OTC

[PATCH] drm/edid: Extract SADs properly from multiple audio data blocks

[Jani Nikula]

On Wed, 09 Mar 2016, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä 
>
> SADs may span multiple CEA audio data blocks in the EDID.
>
> CEA-861-E says:
> "The order of the Data Blocks is not constrained. It is also possible
> to have more than one of a specific type of data block if necessary to
> include all of the descriptors needed to describe the sink’s capabilities."
>
> Each audio data block can carry up to 10 SADs, whereas the ELD SAD limit
> is 15 according to HDA 1.0a spec. So we should support at least two data
> blocks. And apparently some devices take a more liberal interpretation
> and stuff only one SAD per data block even when they would fit into one.
>
> So let's try to extract all the SADs we can fit into the ELD even when
> they span multiple data blocks.
>
> While at it, toss in a comment to explain the 13 byte monitor name
> string limit which confused me at first.
>
> Cc: Arturo Pérez 
> Tested-by: Arturo Pérez 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94197
> Signed-off-by: Ville Syrjälä 
> ---
>  drivers/gpu/drm/drm_edid.c | 17 +++--
>  1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index fdb1eb014586..414d7f61aa05 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -3308,7 +3308,7 @@ void drm_edid_to_eld(struct drm_connector *connector, 
> struct edid *edid)
>   u8 *cea;
>   u8 *name;
>   u8 *db;
> - int sad_count = 0;
> + int total_sad_count = 0;
>   int mnl;
>   int dbl;
>  
> @@ -3322,6 +3322,7 @@ void drm_edid_to_eld(struct drm_connector *connector, 
> struct edid *edid)
>  
>   name = NULL;
>   drm_for_each_detailed_block((u8 *)edid, monitor_name, );
> + /* max: 13 bytes EDID, 16 bytes ELD */
>   for (mnl = 0; name && mnl < 13; mnl++) {
>   if (name[mnl] == 0x0a)
>   break;
> @@ -3350,11 +3351,15 @@ void drm_edid_to_eld(struct drm_connector *connector, 
> struct edid *edid)
>   dbl = cea_db_payload_len(db);
>  
>   switch (cea_db_tag(db)) {
> + int sad_count;
> +
>   case AUDIO_BLOCK:
>   /* Audio Data Block, contains SADs */
> - sad_count = dbl / 3;
> - if (dbl >= 1)
> - memcpy(eld + 20 + mnl, [1], dbl);
> + sad_count = min(dbl / 3, 15 - total_sad_count);

What if total_sad_count > 15? At a glance, this seems to self correct by
subtracting the excess every second time... ;)

BR,
Jani.

> + if (sad_count >= 1)
> + memcpy(eld + 20 + mnl + total_sad_count 
> * 3,
> +[1], sad_count * 3);
> + total_sad_count += sad_count;
>   break;
>   case SPEAKER_BLOCK:
>   /* Speaker Allocation Data Block */
> @@ -3371,13 +3376,13 @@ void drm_edid_to_eld(struct drm_connector *connector, 
> struct edid *edid)
>   }
>   }
>   }
> - eld[5] |= sad_count << 4;
> + eld[5] |= total_sad_count << 4;
>  
>   eld[DRM_ELD_BASELINE_ELD_LEN] =
>   DIV_ROUND_UP(drm_eld_calc_baseline_block_size(eld), 4);
>  
>   DRM_DEBUG_KMS("ELD size %d, SAD count %d\n",
> -   drm_eld_size(eld), sad_count);
> +   drm_eld_size(eld), total_sad_count);
>  }
>  EXPORT_SYMBOL(drm_edid_to_eld);

-- 
Jani Nikula, Intel Open Source Technology Center

[PATCH] drm/edid: Extract SADs properly from multiple audio data blocks

[ville.syrj...@linux.intel.com]

From: Ville Syrjälä 

SADs may span multiple CEA audio data blocks in the EDID.

CEA-861-E says:
"The order of the Data Blocks is not constrained. It is also possible
to have more than one of a specific type of data block if necessary to
include all of the descriptors needed to describe the sink’s capabilities."

Each audio data block can carry up to 10 SADs, whereas the ELD SAD limit
is 15 according to HDA 1.0a spec. So we should support at least two data
blocks. And apparently some devices take a more liberal interpretation
and stuff only one SAD per data block even when they would fit into one.

So let's try to extract all the SADs we can fit into the ELD even when
they span multiple data blocks.

While at it, toss in a comment to explain the 13 byte monitor name
string limit which confused me at first.

Cc: Arturo Pérez 
Tested-by: Arturo Pérez 
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94197
Signed-off-by: Ville Syrjälä 
---
 drivers/gpu/drm/drm_edid.c | 17 +++--
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index fdb1eb014586..414d7f61aa05 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3308,7 +3308,7 @@ void drm_edid_to_eld(struct drm_connector *connector, 
struct edid *edid)
u8 *cea;
u8 *name;
u8 *db;
-   int sad_count = 0;
+   int total_sad_count = 0;
int mnl;
int dbl;

@@ -3322,6 +3322,7 @@ void drm_edid_to_eld(struct drm_connector *connector, 
struct edid *edid)

name = NULL;
drm_for_each_detailed_block((u8 *)edid, monitor_name, );
+   /* max: 13 bytes EDID, 16 bytes ELD */
for (mnl = 0; name && mnl < 13; mnl++) {
if (name[mnl] == 0x0a)
break;
@@ -3350,11 +3351,15 @@ void drm_edid_to_eld(struct drm_connector *connector, 
struct edid *edid)
dbl = cea_db_payload_len(db);

switch (cea_db_tag(db)) {
+   int sad_count;
+
case AUDIO_BLOCK:
/* Audio Data Block, contains SADs */
-   sad_count = dbl / 3;
-   if (dbl >= 1)
-   memcpy(eld + 20 + mnl, [1], dbl);
+   sad_count = min(dbl / 3, 15 - total_sad_count);
+   if (sad_count >= 1)
+   memcpy(eld + 20 + mnl + total_sad_count 
* 3,
+  [1], sad_count * 3);
+   total_sad_count += sad_count;
break;
case SPEAKER_BLOCK:
/* Speaker Allocation Data Block */
@@ -3371,13 +3376,13 @@ void drm_edid_to_eld(struct drm_connector *connector, 
struct edid *edid)
}
}
}
-   eld[5] |= sad_count << 4;
+   eld[5] |= total_sad_count << 4;

eld[DRM_ELD_BASELINE_ELD_LEN] =
DIV_ROUND_UP(drm_eld_calc_baseline_block_size(eld), 4);

DRM_DEBUG_KMS("ELD size %d, SAD count %d\n",
- drm_eld_size(eld), sad_count);
+ drm_eld_size(eld), total_sad_count);
 }
 EXPORT_SYMBOL(drm_edid_to_eld);

-- 
2.4.10