On 17/04/2020 16:29, Laurent Pinchart wrote:
Hi Tomi,
Thank you for the patch.
On Fri, Apr 17, 2020 at 02:41:51PM +0300, Tomi Valkeinen wrote:
If the given videomode does not specify DISPLAY_FLAG_* for the specific
signal property, the driver used a default value. These defaults were
never thought through, as the expectation was that all the DISPLAY_FLAGS
are always set explicitly.
With DRM bridge and panel drivers this is not the case, and while that
issue should be resolved in the future, it's still good to have sane
signal defaults.
This patch changes the defaults to what the hardware has as reset
defaults. Also, based on my experience, I think they make sense and are
more likely correct than the defaults without this patch.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
---
drivers/gpu/drm/omapdrm/dss/dispc.c | 33 ++++++-----------------------
1 file changed, 6 insertions(+), 27 deletions(-)
diff --git a/drivers/gpu/drm/omapdrm/dss/dispc.c b/drivers/gpu/drm/omapdrm/dss/dispc.c
index dbb90f2d2ccd..6639ee9b05d3 100644
--- a/drivers/gpu/drm/omapdrm/dss/dispc.c
+++ b/drivers/gpu/drm/omapdrm/dss/dispc.c
@@ -3137,33 +3137,12 @@ static void _dispc_mgr_set_lcd_timings(struct dispc_device *dispc,
dispc_write_reg(dispc, DISPC_TIMING_H(channel), timing_h);
dispc_write_reg(dispc, DISPC_TIMING_V(channel), timing_v);
- if (vm->flags & DISPLAY_FLAGS_VSYNC_HIGH)
- vs = false;
- else
- vs = true;
-
- if (vm->flags & DISPLAY_FLAGS_HSYNC_HIGH)
- hs = false;
- else
- hs = true;
-
- if (vm->flags & DISPLAY_FLAGS_DE_HIGH)
- de = false;
- else
- de = true;
-
- if (vm->flags & DISPLAY_FLAGS_PIXDATA_POSEDGE)
- ipc = false;
- else
- ipc = true;
-
- /* always use the 'rf' setting */
- onoff = true;
-
- if (vm->flags & DISPLAY_FLAGS_SYNC_POSEDGE)
- rf = true;
- else
- rf = false;
+ vs = !!(vm->flags & DISPLAY_FLAGS_VSYNC_LOW);
+ hs = !!(vm->flags & DISPLAY_FLAGS_HSYNC_LOW);
+ de = !!(vm->flags & DISPLAY_FLAGS_DE_LOW);
+ ipc = !!(vm->flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE);
+ onoff = true; /* always use the 'rf' setting */
+ rf = !!(vm->flags & DISPLAY_FLAGS_SYNC_POSEDGE);
Would it make sense to WARN() if flags are not set, to catch offenders
and fix them ? Apart from that,
Maybe at some point, but for now it would probably be printing WARNs on all boards. I haven't looked
at exactly which driver combinations get the bus flags/formats right, but I have a feeling that it's
not too many.
And some pieces of hardware also may be "don't care" for certain flags, so I think it's a valid case
that a bridge/panel doesn't define some of the flags.
Tomi
--
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Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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