On 28.08.24 15:32, Tomi Valkeinen wrote: > On 26/08/2024 22:35, Jan Kiszka wrote: >> On 24.06.24 12:17, Dmitry Baryshkov wrote: >>> On Mon, 24 Jun 2024 at 13:07, Alexander Stein >>> <alexander.stein@xxxxxxxxxxxxxxx> wrote: >>>> >>>> Hi, >>>> >>>> Am Montag, 24. Juni 2024, 11:49:04 CEST schrieb Dmitry Baryshkov: >>>>> On Mon, Jun 24, 2024 at 03:07:10PM GMT, Aradhya Bhatia wrote: >>>>>> >>>>>> >>>>>> On 22/06/24 17:49, Dmitry Baryshkov wrote: >>>>>>> On Sat, Jun 22, 2024 at 05:16:58PM GMT, Aradhya Bhatia wrote: >>>>>>>> >>>>>>>> >>>>>>>> On 17-Jun-24 13:41, Dmitry Baryshkov wrote: >>>>>>>>> On Mon, Jun 17, 2024 at 07:40:32AM GMT, Jan Kiszka wrote: >>>>>>>>>> On 16.02.24 15:57, Marek Vasut wrote: >>>>>>>>>>> On 2/16/24 10:10, Tomi Valkeinen wrote: >>>>>>>>>>>> Ok. Does anyone have a worry that these patches make the >>>>>>>>>>>> situation >>>>>>>>>>>> worse for the DSI case than it was before? Afaics, if the >>>>>>>>>>>> DSI lanes >>>>>>>>>>>> are not set up early enough by the DSI host, the driver >>>>>>>>>>>> would break >>>>>>>>>>>> with and without these patches. >>>>>>>>>>>> >>>>>>>>>>>> These do fix the driver for DRM_BRIDGE_ATTACH_NO_CONNECTOR >>>>>>>>>>>> and DPI, so >>>>>>>>>>>> I'd like to merge these unless these cause a regression with >>>>>>>>>>>> the DSI >>>>>>>>>>>> case. >>>>>>>>>>> >>>>>>>>>>> 1/2 looks good to me, go ahead and apply . >>>>>>>> >>>>>>>> Isn't there any way for the second patch to move forward as well >>>>>>>> though? >>>>>>>> The bridge device (under DPI to (e)DP mode) cannot really work >>>>>>>> without >>>>>>>> it, and the patches have been pending idle for a long time. =) >>>>>>>> >>>>>>>>>> >>>>>>>>>> My local patches still apply on top of 6.10-rc4, so I don't >>>>>>>>>> think this >>>>>>>>>> ever happened. What's still holding up this long-pending fix >>>>>>>>>> (at least >>>>>>>>>> for our devices)? >>>>>>>>> >>>>>>>>> Neither of the patches contains Fixes tags. If the first patch >>>>>>>>> fixes an >>>>>>>>> issue in previous kernels, please consider following the stable >>>>>>>>> process. >>>>>>>>> >>>>>>>>> If we are unsure about the second patch, please send the first >>>>>>>>> patch >>>>>>>>> separately, adding proper tags. >>>>>>>>> >>>>>>>> >>>>>>>> Thanks Dmitry! I can send the patches again with the required fixes >>>>>>>> tags (or just patch-1 if we cannot do anything about patch-2). >>>>>>> >>>>>>> The problem with the second patch is that it get mixed reviews. I >>>>>>> can >>>>>>> ack the first patch, but for the second one I'd need a >>>>>>> confirmation from >>>>>>> somebody else. I'll go on and apply the first patch later today. >>>>>>> >>>>>> >>>>>> Thanks Dmitry! >>>>>> >>>>>> However, would it be okay if I instead add another patch that makes 2 >>>>>> versions of the "tc_edp_bridge_funcs", say >>>>>> "tc_dpi_edp_bridge_funcs" and >>>>>> "tc_dsi_edp_bridge_funcs", that have all the same function hooks >>>>>> except >>>>>> for the .edid_read()? >>>>>> >>>>>> The dsi edid_read() will remain the same, and Tomi's patch - patch >>>>>> 2/2 - >>>>>> will only fix the dpi version of the edid_read()? >>>>>> >>>>>> The bridge already has the capability to distinguish a DSI input >>>>>> from a >>>>>> DPI input. This can be leveraged to decide which set of functions >>>>>> need >>>>>> to be used without any major changes. >>>>> >>>>> I'd prefer if somebody with the DSI setup can ack / test the second >>>>> patch. >>>>> >>>>> >>>> >>>> Now that my DSI-DP setup works apparently without issue I could test >>>> patch 2. >>>> Since my setup does not use DRM_BRIDGE_ATTACH_NO_CONNECTOR (running on >>>> drivers/gpu/drm/mxsfb/lcdif_drv.c), I can only say >>>> there is no regression. >>> >>> Let me send a (non-tested) patch, switching to drm_bridge_connector, >>> then you can probably test both of them >>> >> >> I suppose [1] was that follow-up, just not leading to success, right? >> >> Now, what's next? I'd love to see the regression we have for the IOT2050 >> devices finally fixed, even if it now only requires a short downstream >> patch. >> >> Jan >> >> [1] >> https://lore.kernel.org/dri-devel/20240624-mxc-lcdif-bridge-attach-v1-1-37e8c5d5d934@xxxxxxxxxx/ > > I have to say I don't remember the details for this anymore, but half a > year ago I said: > >> Afaics, if the DSI lanes are not set up early enough by the DSI host, >> the driver would break with and without these patches. > > I'm not sure if that is correct or not. But if it is, then, afaiu, this > (the second patch): > > - Fixes the issue for the DPI-DP use case > > - Doesn't cause issues for the DSI-DP use case without > DRM_BRIDGE_ATTACH_NO_CONNECTOR (as per Alexander's test) > > - Shouldn't cause (new) issues for the DSI-DP use case with > DRM_BRIDGE_ATTACH_NO_CONNECTOR (as per my code review and guessing...) > > The third point is somewhat concerning, of course, but do we have any > setup with DSI-DP and DRM_BRIDGE_ATTACH_NO_CONNECTOR that works now? If > not, maybe we can just ignore the possible issues, as this fixes > problems on a setup we do have. > As Dmitry asked me during Plumbers to revalidate if our setup still needs patch 2, I just did that over 6.11.0-next-20240923 (where patch 1 is now included). No surprise, it is still needed for our iot2050 device series, otherwise the display remains black. Jan -- Siemens AG, Technology Linux Expert Center
