On Fri, Oct 3, 2014 at 9:42 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Friday 03 October 2014 17:25:13 Mark Rutland wrote: >> > From a system design point, it's still horrible that you have to use >> > DT for a device that is on a discoverable bus like PCI, but as you describe, >> > the reality is that products are shipping that use ath10k PCI devices >> > without this data in them. >> >> I'd see any DT property for this as a workaround, the use of which >> should be discouraged. > > By extension though, any use of DT is really a workaround for the fact > that embedded systems and SoCs don't use discoverable buses, and it should > be discouraged. x86 SoCs actually get this right to a large degree by > making on-chip devices appear as PCI devices that can be used standalone, > although Intel's latest generation SoCs are regressing in this regard > and you still need DT (or something like it) to describe off-chip devices > there. > >> A fun question that springs to mind is can the ath10k chip be removed, >> and if so am I able to place it into a non-DT system (whereupon I have >> no calibration data, so it won't work)? > > Some can be removed, others cannot. If the chip is on a removable pcie > mini card and doesn't have that data on the card itself, it's already > impossible to put it into another system. I don't think we need to solve > that case. Do these minipcie devices have any sort of unique identifier? If so, one could shove the calibration data in /lib/firmware/ath10k/caldata_[CARDID].dat and, as long as that file followed the minipcie card around, it would work just fine. --Andy -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
