On 19.03.2025 00:22, Andi Shyti wrote: > Hi Andy, > > 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. 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). > Andi Heiner
