Removed most CC: SMTP server protested. On 01.09.2021 22:19, Douglas Anderson wrote: > The goal of this patch series is to move away from hardcoding exact > eDP panels in device tree files. As discussed in the various patches > in this series (I'm not repeating everything here), most eDP panels > are 99% probable and we can get that last 1% by allowing two "power > up" delays to be specified in the device tree file and then using the > panel ID (found in the EDID) to look up additional power sequencing > delays for the panel. > > This patch series is the logical contiunation of a previous patch > series where I proposed solving this problem by adding a > board-specific compatible string [1]. In the discussion that followed > it sounded like people were open to something like the solution > proposed in this new series. > > In version 2 I got rid of the idea that we could have a "fallback" > compatible string that we'd use if we didn't recognize the ID in the > EDID. This simplifies the bindings a lot and the implementation > somewhat. As a result of not having a "fallback", though, I'm not > confident in transitioning any existing boards over to this since > we'll have to fallback to very conservative timings if we don't > recognize the ID from the EDID and I can't guarantee that I've seen > every panel that might have shipped on an existing product. The plan > is to use "edp-panel" only on new boards or new revisions of old > boards where we can guarantee that every EDID that ships out of the > factory has an ID in the table. > > Version 3 of this series now splits out all eDP panels to their own > driver and adds the generic eDP panel support to this new driver. I > believe this is what Sam was looking for [2]. > > [1] https://lore.kernel.org/r/YFKQaXOmOwYyeqvM@xxxxxxxxxx/ > [2] https://lore.kernel.org/r/YRTsFNTn%2FT8fLxyB@xxxxxxxxxxxx/ > I like the idea - if something can be configured dynamically lets do it. But I have few questions: 1. Have you read different real panels id's? In many cases (MIPI DSI, LVDS with EDID) manufacturers often forgot to set proper id fields. I do not know how EDID's ids are reliable in case of edp panels. 2. You are working with edp panels - beside EDID they have DPCD which contains things like IEEE_OUI and "Device Identification String", I guess they could be also used for detecting panels, have you considered it? I think DPCD Id should be assigned to EDP-Sink interface, and EDID Id to the actual panel behind it. With this assumption one could consider which timings should be property of which entity. Regards Andrzej
