On Fri, Aug 21, 2015 at 4:38 PM, Johansson, Werner <Werner.Johansson at sonymobile.com> wrote: >> From: Hai Li [mailto:hali at codeaurora.org] >> Sent: den 21 augusti 2015 12:56 >> >> When I made DSI changes, I tried to limit the information in DT (like >> our downstream driver), until there is a case driver really cannot >> figure it out by the existing information. >> I think this is the requirement of upstream kernel. >> >> If we see a panel requires different value in PHY_LN_CFG_4(x) register >> and cannot derive it from any other timings, we could think about >> adding it into DT. > > Not sure how these skew values can be determined from the rest of the timing? > Am I correct in my understanding that these registers would compensate for > differences in physical length of the dsi lanes, or are they designed for a > different purpose? The documentation is very vague on this point. Adjusting > the values down to the default zero still works fine on the other panels (and > enabled the Panasonic panel to work properly too). >
fwiw, if the values are related to the physical cabling/wiring, rather than the panel timing, we should probably get them from DT.. if a combination of the timing and the wiring, that gets a bit more complicated (I am not actually sure myself about these) BR, -R >> Also, I am wondering if this Panasonic WUXGA panel works with >> downstream driver, since I see the same hardcoded values set for all >> the panels. > > We have the Panasonic WUXGA panel working with the downstream driver (it's > shipping in our Xperia Z2 tablets). The problem with our shipping kernel is > that the timing values are derived from the Qualcomm Excel sheet and then > hardcoded (in DT), the timing is not calculated on the fly as is the case > here. It's very easy to just modify hs_zero value up or down one notch > manually when having the timing hardcoded, but such a solution is certainly > not generic. > > Thanks! > /wj > _______________________________________________ > dri-devel mailing list > dri-devel at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel
