On Wed, Mar 19, 2025 at 9:17 AM Heiner Kallweit <hkallweit1@xxxxxxxxx> wrote: > On 19.03.2025 00:22, Andi Shyti wrote: > > On Wed, Mar 19, 2025 at 12:18:47AM +0200, Andy Shevchenko wrote: > >> Wed, Mar 12, 2025 at 08:07:23PM +0100, Heiner Kallweit kirjoitti: > >>> Switch to iomapped register access as a prerequisite for adding > >>> support for MMIO register access. > >> > >> I believe that I at least discussed the similar change a few years ago or even > >> proposed a one. The problem here is that *_p() variants of IO port accessors > >> are not the same as non-_p ones. And commit message is kept silent about > >> possible consequences of this change. > >> > >> So, at bare minumum it would be good to test for some period of time before > >> going for it. > > > > How would you do it? > > Documentation/driver-api/device-io.rst states that the artificially delayed > _p versions were needed on ISA devices. And in general I didn't find any hint > that the non-delayed versions ever caused issues on PCI devices. At least put this in the commit message. It will show that you were aware of _p. > On my system using the non-delayed version works fine, but I can't say 100% > that it's the same for the very first (> 25 yrs ago) chipsets supported by i801. > > Likely users with old systems don't run -next kernels, therefore leaving > this change a full cycle in -next may not really help. We can argue that > we have the -rc period for testing (and reverting if needed). My main concern is to make no regressions for most currently used cases, that's why one cycle in Linux Next is better than none. -- With Best Regards, Andy Shevchenko
