On Mon, 20 Jun 2011, Russell King - ARM Linux wrote: > On Mon, Jun 20, 2011 at 06:58:45PM +0200, Arnd Bergmann wrote: > > We are also going to change the ARM implementation to always do 32 bit > > accesses in readl/writel, but the patch that went into the ehci driver > > was correct nonetheless. > > Not without someone doing a comparitively large amount of work to analyze > the effect of any change there and make sure that it doesn't have a > negative impact to drivers. This thread prompted me to investigate a bit. I have vague memories for the reasons why we decided to use plain C for the IO accessors as the inline assembly version didn't produce nearly the same code quality. It seems that GCC improved quite a bit there, and from a quick investigation, it looks like comparable code is being generated with the C and the inline asm versions with a recent enough GCC. This is certainly the case with the version causing issues with packed structures. Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
