I would move to the Win8+ HAL Model -- a single HAL for APIC, ACPI with runtime support for UEFI (if present) and MP (if present).
If people still want to run on a PIC VM (why???) or old computer, then we can also maintain the HAL PIC x86 for UP. Hence there would only be 2 HALs. Best regards, Alex Ionescu On Mon, Dec 11, 2017 at 1:07 AM, Colin Finck <co...@reactos.org> wrote: > Am 11.12.2017 um 01:18 schrieb Hermès BÉLUSCA-MAÏTO:> If you basically > put all the HALs into one, then you obtain bloated stuff (which remains > in memory for the whole life of the OS). Example: standard HAL is 1MB > vs. ACPI HAL which is few kBHave you actually checked what makes up this > difference? > Hint: hal/halx86/legacy/bus/pci_vendors.ids > > > > Note that if Windows nowadays has only one hal, it's because they now > support basically only one "architecture"/platform, namely, ACPI > multiprocessor (to put it simple). It has its pros, but also a lot of cons. > > That doesn't mean we need to do the same. We can have one HAL for all > (Pentium and newer) x86 platforms. The overhead of additional checks at > boot-up is negligible. That should be a solution for 99% of the people > out there. The rest may still go and trim down our HAL to their needs. > > But let's not pretend we can maintain multiple x86 HALs for all x86 > computers out there. Do you really want to test X HALs with Y different > systems? Ensure that a legacy HAL runs on a modern ACPI system? What > would be the point? > > > > Besides this, I've a question about your observation that in the APIC > hal (not ACPI) there's different implementation of > HalpCalibrateStallExecution and HalpInitializePICs / > HalpInitializeLegacyPIC . Isn't it precisely because these stuff are > completely different from the standard PICs used in platforms for which the > standard HAL (and possibly the ACPI HAL) are used? > > Absolutely not! You need to reprogram the standard PICs also on an APIC > system, and this is precisely what both functions do. Put them into a > diff tool to see for yourself. > > The same goes for timers. Even with the introduction of ACPI Timers, > Local APIC Timers, and Time-Stamp Counters, you still need a traditional > one (like RTC or PIT) for calibration at system startup. Simply because > the newer ones don't run at a known fixed frequency. > The Legacy HAL successfully employs an algorithm based on the RTC while > the APIC HAL unsuccessfully tries to use the PIT. > > > > Actually we should, because the detection might not work (of course in > our simple case "ACPI UP/MP" vs. "Standard", it's simple, but think about > other platforms where there can be subtle differences) > > Tell me about a single one we cannot detect and which is worth to > support. I don't recall that we ever recommended our testers to choose a > different HAL at setup. > > > > And normally it's not the setup that decides about the HAL, but the > bootloader. > > That defies your previous point about the setup initializing the > registry depending on the HAL. > If we can let the user select a Legacy HAL in the boot loader after > installing with an ACPI HAL, it is also technically possible to have one > HAL that encompasses both. > > > - Colin > > _______________________________________________ > Ros-dev mailing list > Ros-dev@reactos.org > http://www.reactos.org/mailman/listinfo/ros-dev >
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