From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Yury V. Umanets" Subject: Re: ACPI vs. ISA IRQs Date: Thu, 06 Nov 2003 11:49:47 +0300 Sender: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Message-ID: <1068108586.1830.12.camel@firefly> References: <1067981294.6057.20.camel@dhcppc4> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1067981294.6057.20.camel-D2Zvc0uNKG8@public.gmane.org> Errors-To: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: Len Brown Cc: ACPI Developers , linux-acpi List-Id: linux-acpi@vger.kernel.org On Wed, 2003-11-05 at 00:28, Len Brown wrote: > Assumption: sharing interrupts is bad. > > Plan: > ACPI should attempt to distribute interrupts across > the available IRQs. > > This mostly applies to PIC mode, where PCI > IRQ Link Devices are available to route PCI > interrupts to open IRQs on the PIC. > (In IO-APIC mode, we generally get no choice > which IO-APIC pins devices are attached to) > > We have acpi_irq_penalty[] (disabled at the moment) > in pci_link.c hard-coded to tell ACPI to avoid some IRQs > that are commonly used by ISA devices. > > But if,say, a sound-blaster card requests exclusive access > to an IRQ that we didn't happen to reserve, and we happened > to set a PCI link device to that IRQ, then sound doesn't > work. > > How to fix? > > We can manually reserve IRQs to over-ride acpi_irq_penalty[], > say "acpi_irq_used=5,10" to tell ACPI not to use IRQs that > it thought by default were available. > > Conversely, we could us, say, "acpi_irq_free=3,15" to tell > ACPI that some IRQs it assumed were reserved for ISA are > actually available for PCI. > > I don't know of an automatic way to handle this. > Seems that the ISA devices use Plug-and-Play methods > to request IRQs, but there is no mechanism for such > an event to boot a PIRQ off an IRQ if ACPI has put it there. > Also, if such a mechanism existed, it wouldn't work > if PNP were not available to ask for an IRQ. > > thoughts? Hello, How about to ask particular bus driver about reserved irqs, etc? > > thanks, > -Len > > ref: > http://bugzilla.kernel.org/show_bug.cgi?id=430 > http://bugzilla.kernel.org/show_bug.cgi?id=1139 > http://bugzilla.kernel.org/show_bug.cgi?id=1391 > > > > > > ------------------------------------------------------- > This SF.net email is sponsored by: SF.net Giveback Program. > Does SourceForge.net help you be more productive? Does it > help you create better code? SHARE THE LOVE, and help us help > YOU! Click Here: http://sourceforge.net/donate/ > _______________________________________________ > Acpi-devel mailing list > Acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org > https://lists.sourceforge.net/lists/listinfo/acpi-devel -- umka ------------------------------------------------------- This SF.net email is sponsored by: SF.net Giveback Program. Does SourceForge.net help you be more productive? Does it help you create better code? SHARE THE LOVE, and help us help YOU! Click Here: http://sourceforge.net/donate/