Hello, On Tue May 19, 2026 at 10:48 AM CEST, tessolveupstream wrote: > > > On 24-04-2026 13:55, Luca Ceresoli wrote: >> Hello, >> >> On Thu Apr 23, 2026 at 11:16 AM CEST, tessolveupstream wrote: >> >>>> I had reached out to TI for clarification and any related documentation >>>> updates, but I have not received any response so far.Given this, it is >>>> uncertain whether we will be able to obtain further details or official >>>> confirmation from TI in the near term. >>>> >>>> I would appreciate your guidance on how you would prefer us to proceed >>>> from here. >>> >>> I followed up with TI, and they pointed us to the relevant sections in the >>> SN65DSI83/84/86 datasheets covering DSI video transmission specifications. >> >> Thanks for keeping on! I'm also trying to get info from TI, I'm keeping you >> up to date if that will happen. >> >>>> https://www.ti.com/lit/ds/symlink/sn65dsi84.pdf?ts=1776924088430&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FSN65DSI84 >>> >>> As per datasheet Section 7.4.7, the device operates in DSI video mode with >>> fixed horizontal timing, where HBP, and HFP are explicitly defined and >>> expected >>> to be present as part of the video line structure. The timing description in >>> this section assumes standard non‑burst video transmission with all >>> horizontal >>> blanking intervals accounted for. >>> >>> The datasheet does not document support for DSI video burst mode, >> >> This sentence seems incorrect. Section 7.4.7 starts with this sentence: >> "The SN65DSI84 supports burst video mode and non-burst video mode ...". >> >> Even though asa matter of fact it looks like many users have issues that >> get solved by disabling burst mode. >> >>> nor does it >>> mention support for omitting horizontal front or back porch intervals. In >>> particular, there is no indication that the device can operate with >>> collapsed >>> or suppressed horizontal blanking, as enabled by MIPI_DSI_MODE_VIDEO_BURST, >>> MIPI_DSI_MODE_VIDEO_NO_HFP, or MIPI_DSI_MODE_VIDEO_NO_HBP. >> >> This is correct. >> >> We can still try to get TI feedback, but it that won't happen in, say, a >> few weeks then I think we should apply this patch. >> > > We have not received any further updates from TI regarding this issue, and > at this point, we are not sure if we will get additional feedback from them. > As you had mentioned earlier that the patch could be considered after > waiting for some time, could you please let us know how we can proceed > further from here?
I am getting some feedback from TI, but it is taking some time. For the time being I think it is clear that HBP and HFP are required, and so removing the MIPI_DSI_MODE_VIDEO_NO_HFP and MIPI_DSI_MODE_VIDEO_NO_HBP in your patch seems to be fully correct, even though this had no effect on the panel I tested. I'm still trying to get some better info to ensure that switching from burst mode to non-burst mode is not expected to have side effects. For thi reason, I think it would be great if you could send a new version with two separate patches: the first one enabling HFP and HBP and which can be applied right away, the second to disable burst mode for which I'd wait a bit longer for TI feedback. You can keep the Tested-by lines. I understand this is painful and taking time, but it's important to ensure as much as possible that the change won't introduce regressions on existing hardware. Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
