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On Wed, Mar 08, 2006 at 11:31:31AM +0900, Tejun Heo wrote: > Greg KH wrote: > >On Fri, Mar 03, 2006 at 06:18:32PM -0500, Jeff Garzik wrote: > > > >>I have a similar situation: > >> > >>BIOS initializes PCI device to mode A, I need to switch it to mode B. > >>To do this, I must assign a value to an MMIO PCI BAR that was not > >>initialized at boot. > >> > >>How to do this? > > > > > >I really don't know, what kind of device wants to do this? > > > > Jeff is probably talking about ABAR of ICH controllers. ABAR (AHCI BAR, > memory mapped IO region covering all AHCI registers) isn't needed for > IDE mode operation and the BAR register is disabled when the chip is in > IDE mode. However, ABAR becomes necessary for 1. accessing SCR registers > (for SATA phy monitor and control) or 2. switching on AHCI mode manually > (some notebook BIOSes always initalize ICH6/7m's into IDE mode even when > the controller does support AHCI mode. > > So, the problem is that the chip actually disables the PCI BAR if > certain switches aren't turned on and thus BIOSes are likely not to > reserve mmio address for the BAR. We can turn on proper switches during > driver initialization but we don't know how to wiggle the BAR into mmio > address space. Thanks for the explaination, that makes more sense. Unfortunatly I do not know how to do this right now :( Anyone with any ideas? thanks, greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||
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