Hi Russell, On Tuesday 18 March 2014 12:56:23 Russell King - ARM Linux wrote: > On Tue, Mar 18, 2014 at 01:41:54PM +0100, Laurent Pinchart wrote: > > Hi Lothar, > > > > That's not my point. I *know* that DE is a data gating signal with a > > polarity already defined by the DRM_MODE_FLAG_POL_DE_(LOW|HIGH) flags. > > Like all other signals it gets generated on a clock edge and is sampled > > on a clock edge. The DRM_MODE_FLAG_POL_DE_*EDGE flags proposed above > > describe seem to describe just that, *not* the signal polarity. I thus > > want to know whether there are systems where the data signals and the DE > > signal need to be sampled on different edges of the pixel clock. > > That's not relevant to this patch series though. This patch series is > about adding configuration which will allow iMX6 SoCs to be properly > configured for their displays. > > iMX has the ability to: > > - define the polarity of the clock signal > - define the polarity of the other signals > > It does not have the ability to define which clock edge individual signals > like vsync (frame clock), hsync (line clock), disable enable change on > independently. > > So, it doesn't make sense _here_ for the display enable to be defined by > an edge - it's not something that can be changed here. What can only be > changed is it's active level. > > Of course, there may be some which can do this, and that's a separate > problem that would need to be addressed when there's hardware that does > support it. > > The objection which Lothar is raising is that _this_ definition does not > match the _hardware_ capabilities which it is intended to be used with, > which is a very valid objection. Thank you for the clarification. That absolutely makes sense. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
