Messages in this thread | | | Date | Wed, 26 Feb 2003 12:46:50 -0800 | From | "Randy.Dunlap" <> | Subject | Re: [2.5.63 PATCH][TRIVIAL]Change rtc.c ioport extend from 10h to 8h |
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On Wed, 26 Feb 2003 15:29:06 -0500 (EST) "Richard B. Johnson" <root@chaos.analogic.com> wrote:
| On 26 Feb 2003, Rusty Lynch wrote: | | > On Wed, 2003-02-26 at 11:35, Richard B. Johnson wrote: | > > On 26 Feb 2003, Rusty Lynch wrote: | > > | > > > The real time clock only needs 8 bytes, but rtc.c is reserving 10h bytes. | > > [SNIPPED...] | > > | > > It only needs two bytes port 0x70 and port 0x71 in ix86. Since the Sparc | > > gets addressed differently and can only read/write words, it needs 8 | > > bytes. Please, if you are going to fix it, please fix it only once by | > > setting a different length for the different machines! | > > Cheers, | > > Dick Johnson | > | > Actually, it's finer grain then x86, it's a chipset issue. As Randy | > pointed out in the original thread ==> | > > Some Intel chipset specs list RTC as using 0x70 - 0x77, probably with | > > some aliasing in there, so it looks to me like an EXTENT of 8 would be | > > safer and still allow you access to 0x79. | > > | > > I'm looking at 82801BA-ICH2, 82801-ICH3, and 82801AA-ICH0 specs. | > > | > > -- | | Can't see what an IDE chip-set has to do with it. The RTC can only | be accessed as an offset-location and a data-location. You write | an offset at one location and you read/write data at another location. | On an ix86, the locations are adjacent byte-wide ports. On the Sparc | they are adjacent dword-wide memory locations.
IDE is just 1 of about 20 functional units in those chipsets. The chipset specs say that there are some other RTC registers there (total of 8). Reducing the RTC I/O space from 16 to 8 bytes looks right to me, even on x86.
| Cheers, -- ~Randy - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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