On 4/4/22 18:01, Rob Herring wrote:
On Sat, Apr 02, 2022 at 07:55:59PM +0200, Marek Vasut wrote:
On 4/2/22 19:08, Noralf Trønnes wrote:
Den 02.04.2022 18.39, skrev Marek Vasut:
On 4/2/22 09:45, Noralf Trønnes wrote:
Den 02.04.2022 06.28, skrev Marek Vasut:
On 4/2/22 05:19, Laurent Pinchart wrote:
On Fri, Apr 01, 2022 at 10:36:24PM +0200, Marek Vasut wrote:
On 4/1/22 20:46, Laurent Pinchart wrote:
On Fri, Apr 01, 2022 at 06:37:54PM +0200, Marek Vasut wrote:
Make the width-mm/height-mm panel properties mandatory in
of_get_drm_panel_display_mode(), print error message and
return -ve in case these DT properties are not present.
This is needed to correctly report panel dimensions.
Can we guarantee this won't cause a regression ?
For the upstream DTs, I think we can.
For downstream DTs, we cannot know.
Are there users of this function whose DT bindings don't require the
width-mm and height-mm properties ?
There is literally one user of this function upstream:
drivers/gpu/drm/tiny/panel-mipi-dbi.c
Yes, the function was added for that driver since it was so generic in
nature. What about adding an argument to of_get_drm_panel_display_mode()
that tells if the properties are mandatory or not?
Sure, we can do that, but maybe the question here is even bigger than
this series.
Should every panel set mandatory width_mm/height_mm so e.g. the user
space can infer DPI from it and set up scaling accordingly, or should
width_mm/height_mm be optional ?
I think width_mm/height_mm should be mandatory for all panels.
Thoughts ?
If this had come up during the review of the driver I would have no
problem making it mandatory. It makes sense for DPI. Maybe it's possible
to get around the ABI break by getting in a change through -fixes before
5.18 is released? I'm fine with that.
Well that's awesome, the dbi-spi.yaml didn't land in any kernel release yet,
so we still have a chance to fix it ? Rob ?
Yes, it can be fixed. And the binding, not the kernel, is the place to
enforce it being mandatory IMO.
All right, I sent 1/3 separately with Fixes: tag, so it can be applied .
