Date: Mon, 09 Jul 2001 12:58:31 -0600 From: Warner Losh <imp@harmony.village.org> To: tlambert2@mindspring.com Cc: Peter Wemm <peter@wemm.org>, Mike Smith <msmith@FreeBSD.ORG>, Makoto MATSUSHITA <matusita@jp.FreeBSD.org>, sos@freebsd.dk, current@FreeBSD.ORG Subject: Re: Problems with ata probing twice. Message-ID: <200107091858.f69IwVJ20839@harmony.village.org> In-Reply-To: Your message of "Mon, 09 Jul 2001 11:55:36 PDT." <3B49FE28.AEE25978@mindspring.com> References: <3B49FE28.AEE25978@mindspring.com> <20010707215344.4B1F2380F@overcee.netplex.com.au> <200107072254.f67MsiJ73462@harmony.village.org>
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In message <3B49FE28.AEE25978@mindspring.com> Terry Lambert writes: : Warner Losh wrote: : > That is, I advocate all busses that support sharing to or in : > RF_SHAREABLE when appropriate. The trouble is that with the current : > interfaces, that precludes one from using fast interrupts. FAST or : > not fast is a property of bus_setup_intr, not bus_alloc_resource. sio : > is the only driver in the tree using fast interrupts (although there : > are several not in the tree by third parties that use this) right now, : > and it treats the INTR_FAST bit as a strong hint only. : : The problem with this is drivers that can't share : interrupts because there is no way to ask the hardware : which of several devices caused the interrupt. This : means that it's an attribute of the driver, not the : bus, so having the bus do this automatically would not : be correct. Give me an example of hardware that does this. I know of no devices in the tree that do this.... : > [*] Even on ISA systems, one can share interrupts to a limited : > extent. The two pccards could share interrupts (with the right magic : > programmed on some ISA chipsets). The pccards could share with the : > CSC interrupt (aka management interupt), but again this requires : > special magic on some bridges, none on others and isn't supported at : > all on still others). Some pccard bridge chipsets let you HI-Z IRQ 15 : > or 14 and thus share them with the IDE controller. I've disallowed : > all these sharing potentials because you'll notice a fair number of : > weasel words in the previous sentences (some, might, magic). : : I've frequently thought that the COM1/COM3 and COM2/COM4 : interrupt duality should be permitted, with FreeBSD doing : the interlock based on only permitting one of the pair to : be open at a time: that is, the interrupt gets set up for : one or the other of them based on what's open and what's : not. Historically, internal modems have liked to be on : COM3 or COM4, yet you are stuck with the internal serial : ports glomming onto the interrupts. That's a different problem. Warner To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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