Re: [igt-dev] [PATCH] lib/igt_kms.c igt_kms.h: tile property parser

["Tolakanahalli Pradeep, Madhumitha" <madhumitha.tolakanahalli.pradeep@intel.com>]

Thank you for your comments, Simon.

I have taken care of the comments regarding style changes.

On Thu, 2019-07-18 at 07:24 +0100, Ser, Simon wrote:
> Hi,
> 
> Here are a few comments.
> 
> On Wed, 2019-07-17 at 11:10 -0700, Madhumitha Tolakanahalli Pradeep
> wrote:
> > The tile property parser parses the connector tile property
> > obtained
> > from connector's Display ID block and set per connector.
> > 
> > Cc: Manasi Navare <manasi.d.navare@intel.com>
> > Cc: Petri Latvala <petri.latvala@intel.com>
> > Signed-off-by: Madhumitha Tolakanahalli Pradeep <
> > madhumitha.tolakanahalli.pradeep@intel.com>
> > ---
> >  lib/igt_kms.c | 26 ++++++++++++++++++++++++++
> >  lib/igt_kms.h | 11 +++++++++++
> >  2 files changed, 37 insertions(+)
> > 
> > diff --git a/lib/igt_kms.c b/lib/igt_kms.c
> > index 175e71c3..846314de 100644
> > --- a/lib/igt_kms.c
> > +++ b/lib/igt_kms.c
> > @@ -4511,3 +4511,29 @@ bool
> > igt_display_has_format_mod(igt_display_t *display, uint32_t format,
> >  
> >  	return false;
> >  }
> > +
> > +/**
> > + * igt_parse_connector_tile_blob:
> > + * @blob: pointer to the connector's tile properties
> > + * @tile: pointer to tile structure that is populated by the
> > function
> > + *
> > + * Parses the connector tile blob to extract the tile information
> > + *
> > + */
> > +
> > +void igt_parse_connector_tile_blob(drmModePropertyBlobPtr blob,
> > +				igt_tile_info_t * tile)
> 
> Style: align with as many tabs as possible, then fill the rest with
> spaces.
> 
> > +{
> > +	char * blob_data = blob->data;
> 
> Style: no space after star.
> 
>     char *thing = stuff;
> 
> Applies to the whole patch.
> 
> > +	if(blob) {
> 
> Style: space after if keyword.
> 
> > +		tile->tile_group_id = atoi(strtok(blob_data, ":"));
> 
> This segfaults if the field doesn't exist. It would be nicer to
> igt_assert that strtok doesn't return NULL. Maybe with a wrapper
> function? e.g.
> 
>     static int parse_next_tile_field(char *data)

This blob information is obtained from the kernel
(drm/drm_connector.c). It's format is defined in
drm_connector_set_tile_property() to be of the form of 8 integers using
':' as a separator. Hence, the field not existing wouldn't be a
possibility, which is why no NULL return checks are being performed.

> Also this doesn't check for integer overflows, but not sure it's
> worth
> the hassle.
> 
> > +		tile->tile_is_single_monitor = atoi(strtok(NULL, ":"));
> > +		tile->num_h_tile = atoi(strtok(NULL, ":"));
> > +		tile->num_v_tile = atoi(strtok(NULL, ":"));
> > +		tile->tile_h_loc = atoi(strtok(NULL, ":"));
> > +		tile->tile_v_loc = atoi(strtok(NULL, ":"));
> > +		tile->tile_h_size = atoi(strtok(NULL, ":"));
> > +		tile->tile_v_size = atoi(strtok(NULL, ":"));
> > +	}
> > +}
> > diff --git a/lib/igt_kms.h b/lib/igt_kms.h
> > index 0486737b..08483505 100644
> > --- a/lib/igt_kms.h
> > +++ b/lib/igt_kms.h
> > @@ -387,6 +387,14 @@ struct igt_display {
> >  	int format_mod_count;
> >  };
> >  
> > +typedef struct {
> > +	int tile_group_id;
> > +	bool tile_is_single_monitor;
> > +	uint8_t num_h_tile, num_v_tile;
> > +	uint8_t tile_h_loc, tile_v_loc;
> > +	uint16_t tile_h_size, tile_v_size;
> 
> I wouldn't repeat the tile_ prefix for all of these fields, it's
> already clear that it's about the tile from the type name.

The naming convention of the tile properties confroms to that in the
kernel to maintain uniformity.

> 
> > +} igt_tile_info_t;
> 
> I'm personally not a fan of typedefs, but it seems like the rest of
> IGT
> doesn't care, so it's probably fine.
> 
> >  void igt_display_require(igt_display_t *display, int drm_fd);
> >  void igt_display_fini(igt_display_t *display);
> >  void igt_display_reset(igt_display_t *display);
> > @@ -835,4 +843,7 @@ static inline bool igt_vblank_before(uint32_t
> > a, uint32_t b)
> >  	return igt_vblank_after(b, a);
> >  }
> >  
> > +void igt_parse_connector_tile_blob(drmModePropertyBlobPtr blob,
> > +			igt_tile_info_t * tile);
> > +
> >  #endif /* __IGT_KMS_H__ */
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