On Wed, 2009-05-06 at 15:09 +1000, Dave Airlie wrote: > On Wed, 2009-05-06 at 01:56 -0300, Tiago Vignatti wrote: > > Dave Airlie escreveu: > > > On Wed, 2009-05-06 at 01:37 -0300, Tiago Vignatti wrote: > > >> Hi, > > >> > > >> AFAIK, the existing interface in libpciaccess to enable a device > > >> (pci_device_enable) deals always with I/O _and_ memory resources. But > > >> I'm confused with the behavior of such interface because it's not > > >> working as I expected. For me it has to be equivalent to do the > > >> following, in the regs configuration space: > > >> > > >> ctrl = (PCI_COMMAND_IO | PCI_COMMAND_MEMORY); > > >> pci_device_cfg_write_u32(dev, ctrl, PCI_COMMAND); > > >> > > >> > > >> Isn't it? But it's not happening that. When I call pci_device_enable (or > > >> just `echo 1 > enable` in device) the kernel sometimes sets only the > > >> PCI_COMMAND_MEMORY bit or simply does nothing. What am I missing here? > > >> > > >> Attached, I'm sending a code that I'm using to play with this. > > > > > > Its not for that. > > > > > > Twiddling enable bits from userspace isn't something we want to be able > > > to do. > > > > So what's the intention of the enable field in sysfs? > > > > What I want in the end is to build an interface inside pci library to > > enable/disable a given resource of a device. This is what we were doing > > in Xorg (sigh) and what we progressively can move out to libpciaccess to > > build (I expected in a near future) the "system-wide PCI access control". > > The enable field is to let you *enable* cards that haven't been yet. > > This is just so secondary cards MMIO ranges are enabled. However it > won't disable anything for you ever. > > Machines boot with the secondary disabled, this just lets you enable it, > and generally once enabled you can read out the ROM at least. > > You are not allowed enable/disable PCI device resources from X.org. This > isn't the X servers job at all ever again. > > Start to think of X as a non-priv process and design things accordingly. > > Dave. Perhaps I haven't explained it, but why do we need to ever play with a *PCI* resource? Linux does all the PCI setup for us, we never get overlapping PCI resources. VGA should be the only thing we are missing. Dave. > > > _______________________________________________ > xorg-devel mailing list > xorg-devel@xxxxxxxxxxx > http://lists.x.org/mailman/listinfo/xorg-devel -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
