Re: [RFC PATCH 00/17] drm: bridge: Samsung MIPI DSIM bridge

Hi Tim

On Tue, Oct 5, 2021 at 11:43 PM Tim Harvey [off-list ref] wrote:

On Sun, Jul 25, 2021 at 10:14 AM Jagan Teki [off-list ref] wrote:

quoted

Hi Sam,

On Sun, Jul 25, 2021 at 10:35 PM Sam Ravnborg [off-list ref] wrote:

quoted

Hi Jagan,

On Sun, Jul 04, 2021 at 02:32:13PM +0530, Jagan Teki wrote:

quoted

This series supports common bridge support for Samsung MIPI DSIM
which is used in Exynos and i.MX8MM SoC's.

The final bridge supports both the Exynos and i.MX8MM DSI devices.

Right now bridge offers two sets of implementations.

A. With component_ops and exynos specific code exclusively for
   exynos dsi drivers and it's legacy bindings.

B. Without componenet_ops for newly implemented bridges and its
   users like i.MX8MM.

The future plan is to fix the implementation A) by dropping
component_ops and fixing exynos specific code in order to make
the bridge more mature to use and the same is mentioned in
drivers TODO.

Patch 0001 - 0006: Bridge conversion
Patch 0007 - 0017: Samsung MIPI DSIM bridge fixes, additions

Tested in Engicam i.Core MX8M Mini SoM.

Anyone interest, please have a look on this repo
https://github.com/openedev/linux/tree/070421-imx8mm-dsim

Would appreciate anyone from the exynos team to test it on
the exynos platform?

Any inputs?

I really like where you are headign with this!
No testing - sorry. But I will try to provide a bit of feedback on the
individual patches.

I hope you find a way to move forward with this.

Thanks for the response.

We have found some issues with Bridge conversion on existing exynos
drivers. The component based DSI drivers(like exynos) are difficult to
attach if it involves kms hotplug. kms hotplug would require drm
pointer and that pointer would only available after the bind call
finishes. But the bridge attach in bind call will defer till it find
the attached bridge.

Right now I'm trying to find the proper way to attach the bridges for
component based DSI drivers which involves kms hot-plug.

If you have any ideas on this, please let me know.

Jagan,

How is your progress on this series? Looking at your repo it looks
like you've rebased on top of 5.13-rc3 in your 070121-imx8mm-dsim
branch but you've got a lot of things there that are likely not
related to this series?

I have a bit of work on those patches and tested on imx8mn. Basically:

- add the dsi timing calculation
- change few difference with samsung bridge
- fix crashes of my dsi panels
- compare with NXP driver the final results

I found that I have one problem that gives me some instability. In the
NXP original driver the panel needs to be
enabled in bridge_enable before out the standby. If I understand
correctly, our standby should be done after.
I would like to have some feedback and help and testing on other
boards/devices and some suggestions on how to handle
some of the differences. Another big problem is etnavi that is not stable

Michael

Best regards,

Tim

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