[PATCH] add boot option to control Intel SATA/PATA combined mode (2bd0fa3b) · Commits · 戴 / test

Combined mode sucks. Especially when both libata and the legacy IDE drivers try to drive ports on the same device, since that makes DMA rather difficult. This patch addresses the problem by allowing the user to control which driver binds to the ports in a combined mode configuration. In many cases, they'll probably want the libata driver to control both ports since it can use DMA for talking with ATAPI devices (when libata.atapi_enabled=1 of course). It also allows the user to get old school behavior by letting the legacy IDE driver bind to both ports. But neither is forced, the patch doesn't change current behavior unless one of combined_mode=ide or combined_mode=libata is passed on the boot line. Either of those options may require you to access your devices via different device nodes (/dev/hd* in the ide case and /dev/sd* in the libata case), though of course if you have udev installed nicely you may not notice anything. :) Let me know if the documentation is too cryptic, I'd be happy to expand on it if necessary. I think most users will want to boot with 'combined_mode=libata' and add 'options libata atapi_enabled=1' to their modules.conf to get good DVD playing and disk behavior (haven't tested CD or DVD writing though). I'd much rather things behave sanely by default (i.e. DMA for devices on both ports), but apparently that's difficult given the various chip bugs and hardware configs out there (not to mention that people's drives may suddenly change from /dev/hdc to /dev/sdb), so this boot option may be the correct long term fix. Signed-off-by:

Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by:

Jeff Garzik <jgarzik@pobox.com>

Documentation/kernel-parameters.txt

+8 −0

Original line number	Diff line number	Diff line
		@@ -633,6 +633,14 @@ running once the system is up.
		inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
		Format: <irq>

		combined_mode= [HW] control which driver uses IDE ports in combined
		mode: legacy IDE driver, libata, or both
		(in the libata case, libata.atapi_enabled=1 may be
		useful as well). Note that using the ide or libata
		options may affect your device naming (e.g. by
		changing hdc to sdb).
		Format: combined (default), ide, or libata

		inttest= [IA64]

		io7= [HW] IO7 for Marvel based alpha systems

drivers/pci/quirks.c

+30 −0

Original line number	Diff line number	Diff line
		@@ -1098,6 +1098,23 @@ static void __init quirk_alder_ioapic(struct pci_dev *pdev)
		DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_EESSC, quirk_alder_ioapic );
		#endif

		enum ide_combined_type { COMBINED = 0, IDE = 1, LIBATA = 2 };
		/* Defaults to combined */
		static enum ide_combined_type combined_mode;

		static int __init combined_setup(char *str)
		{
		if (!strncmp(str, "ide", 3))
		combined_mode = IDE;
		else if (!strncmp(str, "libata", 6))
		combined_mode = LIBATA;
		else /* "combined" or anything else defaults to old behavior */
		combined_mode = COMBINED;

		return 1;
		}
		__setup("combined_mode=", combined_setup);

		#ifdef CONFIG_SCSI_SATA_INTEL_COMBINED
		static void __devinit quirk_intel_ide_combined(struct pci_dev *pdev)
		{
		@@ -1164,6 +1181,19 @@ static void __devinit quirk_intel_ide_combined(struct pci_dev *pdev)
		if (prog & comb)
		return;

		/* Don't reserve any so the IDE driver can get them (but only if
		* combined_mode=ide).
		*/
		if (combined_mode == IDE)
		return;

		/* Grab them both for libata if combined_mode=libata. */
		if (combined_mode == LIBATA) {
		request_region(0x1f0, 8, "libata"); /* port 0 */
		request_region(0x170, 8, "libata"); /* port 1 */
		return;
		}

		/* SATA port is in legacy mode. Reserve port so that
		* IDE driver does not attempt to use it. If request_region
		* fails, it will be obvious at boot time, so we don't bother

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