Messages in this thread | | | Date | Tue, 29 Nov 2005 16:54:21 -0500 | From | Jeff Garzik <> | Subject | Re: [PATCH] add boot option to control Intel combined mode behavior (to allow DMA in combined mode configs!) |
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Jesse Barnes wrote: > 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 intel_combined_mode=ide or intel_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 > 'intel_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). > > Documentation/kernel-parameters.txt | 7 +++++++ > drivers/pci/quirks.c | 30 ++++++++++++++++++++++++++++ > > 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>
Seems like it should work. I presume you tested this?
Remove the 'intel_' prefix from the kernel parameter, since this concept applies to other controllers as well. Otherwise, seems OK.
Jeff
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