Re: [PATCH v2 0/2] drm: bridge: ti-sn65dsi83: Improve dual-link LVDS support

[Alexander Stein]

Am Mittwoch, 25. März 2026, 07:09:07 CET schrieb tessolveupstream@xxxxxxxxx:
> 
> On 24-03-2026 16:40, Alexander Stein wrote:
> > Am Dienstag, 24. März 2026, 12:00:43 CET schrieb tessolveupstream@xxxxxxxxx:
> >> [snip]
> >>> Thanks for the detailed explanation.
> >> Regarding the panel timings, they are not explicitly defined in the DTS. 
> >> The panel is currently using the timings provided by the panel driver 
> >> (panel-simple.c), specifically:
> >>
> >> static const struct display_timing auo_g133han01_timings = {
> >>         .pixelclock = { 134000000, 141200000, 149000000 },
> >>         .hactive = { 1920, 1920, 1920 },
> >>         .hfront_porch = { 39, 58, 77 },
> >>         .hback_porch = { 59, 88, 117 },
> >>         .hsync_len = { 28, 42, 56 },
> >>         .vactive = { 1080, 1080, 1080 },
> >>         .vfront_porch = { 3, 8, 11 },
> >>         .vback_porch = { 5, 14, 19 },
> >>         .vsync_len = { 4, 14, 19 },
> >> };
> >>
> >> The panel I am using is based on AUO G133HAN01, and the datasheet can 
> >> be found here:
> >> https://datasheet4u.com/pdf/1257948/G133HAN01.0.pdf > About CHA_DSI_CLK_RANGE: what is your DSI clock?
> >>>
> >>
> >> In the current working configuration, the measured clock frequencies 
> >> are:
> >> DSI_CLK: ~422MHz
> >> LVDS_CLK(both A & B Channels): ~70MHz
> >>> Finally I don't think the swing values are problematic, so I'd leave them
> >>> as the last thing to check.
> > 
> > I managed to get this display running with this DSI->LVDS bridge on
> > TQMa8MxML/TQMa8MxNL (imx8mm or imx8mn) platform.
> > See [1] for the DT. What platform/ DSI host are you using?
> >
> 
> Thanks for sharing your setup.
> 
> I am currently working on the Qualcomm QCS615 platform. The setup 
> is as follows:
> 
> - SoC: QCS615
> - Bridge: TI SN65DSI84 (DSI to dual-link LVDS)
> - Panel: AUO G133HAN01
> 
> I am currently using the following DT overlay:
> (talos-evk-lvds-auo,g133han01.dtso)
> https://lore.kernel.org/all/20260302121159.1938694-1-tessolveupstream@xxxxxxxxx/T/#m00e90e7ff95915bbdb21dbd786c232526e3360a2

I don't know your SoC, but at a first glance the DT looks okay.

> Could you please confirm whether the display was brought up on your platform 
> using only the DT changes you shared, without requiring any driver 
> modifications?

Yes, no modifications on the driver. Do you see any picture on your display?
Initialization of these DSI-to-X bridges is a mess. Most of them need LP-11
on the DSI (clock/data0?) lanes upon reset.
I've also read that some DSI hosts (Raspberry Pi?) adjust the display timings
in hardware as well. Also make sure your burst clock is high enough.

Best regards,
Alexander

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