On 05.04.2017 14:04, Thierry Reding wrote: > On Wed, Apr 05, 2017 at 10:52:32AM +0200, Lucas Stach wrote: >> Hi Rob, >> >> Am Mittwoch, den 29.03.2017, 08:56 -0500 schrieb Rob Herring: >>> On Mon, Jan 23, 2017 at 10:33 AM, Thierry Reding >>> <thierry.reding@xxxxxxxxx> wrote: >>>> On Fri, Jan 13, 2017 at 06:36:30PM +0100, Lucas Stach wrote: >>>>> The i2c adapter on DP AUX is purely a software construct. Linking >>>>> it to the device node of the parent device is wrong, as it leads to >>>>> 2 devices sharing the same device node, which is bad practice, as >>>> Who says that two devices can't share the same device node? It's done >>>> all the time. >>> It's done *some of the time* and I would not consider it best practice. >>> >>>>> well as the i2c trying to populate children of the i2c adapter by >>>>> looking at the child device nodes of the parent device. >>>> A set of patches landed in v4.9 to work around this issue in a better >>>> way. See: >>>> >>>> 98b00488459e dt-bindings: i2c: Add support for 'i2c-bus' subnode >>>> 7e4c224abfe8 i2c: core: Add support for 'i2c-bus' subnode >>> What does this buy us? I don't see why this needs to be in DT either. >>> Contrary to popular belief, DT is not the only way to instantiate >>> devices, C code can still do it. >>> >>> Also, if this one line removal has no side effects, then how was it >>> even needed? We can always add it back if there's some argument for >>> why it is needed. >> Okay, so I take this as you mostly agreeing with the rationale of this >> patch. > For some general background on this: I was originally using this for DP > support on Tegra (though that ended up never getting merged because of a > particularily frustrating episode of trying to get better link training > support into the core helpers) and use it as a means to obtain the I2C > controller used for DDC. On Tegra, and I suspect other devices as well, > the DP AUX controller is separate from the encoder, so the idea was to > link them together using a standard ddc-i2c-bus phandle. > > I ended up not needing that because the encoder and DP AUX controller > are so tightly linked on Tegra that I need direct access to the DP AUX > anyway and can therefore directly get the I2C controller from that. > > If there aren't any other users of this, I suppose we could simply > remove the line. Should someone turn up in the future and require the > I2C controller to be looked up from a phandle we could add it again, > at which point we'd have to investigate again how to get rid of the > errors. > > Acked-by: Thierry Reding <treding@xxxxxxxxxx> It looks like the patch has been accepted but not merged. Who can pick it up? or is it OK if I put it int drm-misc? Regards Andrzej _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
