Re: [PATCH] drm/edid: Support type 7 timings

On Wed, 19 Jan 2022, Yaroslav Bolyukin iam@lach.pw wrote:

Per VESA DisplayID Standard v2.0: Type VII Timing – Detailed Timing Data

Definitions were already provided as type I, but not used

Thanks for the patch. Functionally I think it looks correct, and something we'll want. I do have some nitpicks though, comments inline.

For the next version, please consider Cc'ing the intel-gfx list as well to get our CI results on it too.

BR, Jani.

Signed-off-by: Yaroslav Bolyukin iam@lach.pw

drivers/gpu/drm/drm_edid.c | 26 +++++++++++++++++--------- include/drm/drm_displayid.h | 6 +++--- 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 12893e7be..5fcefd9b5 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -5404,13 +5404,17 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi return quirks; }

-static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *dev,

• 					    struct displayid_detailed_timings_1 *timings)
  

+static struct drm_display_mode *drm_mode_displayid_detailed_1_7(struct drm_device *dev,

• 						struct displayid_detailed_timings_1_7 *timings,
  

• 						bool type_7)
  

I think the function rename here is unnecessary.

{ struct drm_display_mode *mode; unsigned pixel_clock = (timings->pixel_clock[0] | (timings->pixel_clock[1] << 8) | (timings->pixel_clock[2] << 16)) + 1;

• // type 7 allows higher precision pixel clock

Please don't use // style comments.

For the comment contents, I think you should just state the units for each; 10 kHz for type I, kHz for type VII.

• if (!type_7)

• pixel_clock *= 10;
  

Please don't mix declarations and code.

unsigned hactive = (timings->hactive[0] | timings->hactive[1] << 8) + 1; unsigned hblank = (timings->hblank[0] | timings->hblank[1] << 8) + 1; unsigned hsync = (timings->hsync[0] | (timings->hsync[1] & 0x7f) << 8) + 1; @@ -5426,7 +5430,7 @@ static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *d if (!mode) return NULL;

• mode->clock = pixel_clock * 10;

• mode->clock = pixel_clock;

Since we used to have the multiplication here (and we don't mix declarations and code anyway) I'd keep it here.

Maybe:

mode->clock = type_7 ? pixel_clock : pixel_clock * 10;

mode->hdisplay = hactive; mode->hsync_start = mode->hdisplay + hsync; mode->hsync_end = mode->hsync_start + hsync_width; @@ -5449,10 +5453,12 @@ static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *d return mode; }

-static int add_displayid_detailed_1_modes(struct drm_connector *connector,

• 			  const struct displayid_block *block)
  

+static int add_displayid_detailed_1_7_modes(struct drm_connector *connector,

• 			    const struct displayid_block *block,
  

• 			    bool type_7)
  

{

• struct displayid_detailed_timing_block *det = (struct displayid_detailed_timing_block *)block;

• struct displayid_detailed_timing_1_7_block *det =

• (struct displayid_detailed_timing_1_7_block *)block;
  

I think the displayid_detailed_timing_block -> displayid_detailed_timing_1_7_block rename is unnecessary.

int i; int num_timings; struct drm_display_mode *newmode; @@ -5463,9 +5469,9 @@ static int add_displayid_detailed_1_modes(struct drm_connector *connector,

num_timings = block->num_bytes / 20; for (i = 0; i < num_timings; i++) {

• struct displayid_detailed_timings_1 *timings = &det->timings[i];
  

• struct displayid_detailed_timings_1_7 *timings = &det->timings[i];
  
  

• newmode = drm_mode_displayid_detailed(connector->dev, timings);
  

• newmode = drm_mode_displayid_detailed_1_7(connector->dev, timings, type_7);
  

  if (!newmode) continue;

@@ -5485,7 +5491,9 @@ static int add_displayid_detailed_modes(struct drm_connector *connector, displayid_iter_edid_begin(edid, &iter); displayid_iter_for_each(block, &iter) { if (block->tag == DATA_BLOCK_TYPE_1_DETAILED_TIMING)

• 	num_modes += add_displayid_detailed_1_modes(connector, block);
  

• 	num_modes += add_displayid_detailed_1_7_modes(connector, block, false);
  

• else if (block->tag == DATA_BLOCK_2_TYPE_7_DETAILED_TIMING)
  

• 	num_modes += add_displayid_detailed_1_7_modes(connector, block, true);
  

I'd probably not add a true/false parameter here, since we pass in block anyway, and the function can have and initialize the bool local variable internally based on block->tag.

} displayid_iter_end(&iter);

diff --git a/include/drm/drm_displayid.h b/include/drm/drm_displayid.h index 7ffbd9f7b..268ff5e1f 100644 --- a/include/drm/drm_displayid.h +++ b/include/drm/drm_displayid.h @@ -111,7 +111,7 @@ struct displayid_tiled_block { u8 topology_id[8]; } __packed;

-struct displayid_detailed_timings_1 { +struct displayid_detailed_timings_1_7 { u8 pixel_clock[3]; u8 flags; u8 hactive[2]; @@ -124,9 +124,9 @@ struct displayid_detailed_timings_1 { u8 vsw[2]; } __packed;

-struct displayid_detailed_timing_block { +struct displayid_detailed_timing_1_7_block {

Like I said, I wouldn't rename this.

struct displayid_block base;

• struct displayid_detailed_timings_1 timings[];

• struct displayid_detailed_timings_1_7 timings[];

};

#define DISPLAYID_VESA_MSO_OVERLAP GENMASK(3, 0)

base-commit: 99613159ad749543621da8238acf1a122880144e