On Thu, Jun 18, 2015 at 1:01 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > On Thu, May 28, 2015 at 07:41:12AM -0500, Bjorn Helgaas wrote: >> >> > > I'd like res->flags to reflect the capabilities of the hardware, not >> > > whether the window is currently enabled. >> > > >> > Flag bits seem to be all taken. Could we use IORESOURCE_DISABLED for that >> > purpose, or could that cause conflicts elsewhere ? >> >> Yes, I think IORESOURCE_DISABLED would be appropriate for any I/O windows >> below a host bridge that doesn't support I/O space. >> > I integrated Lorenzo's patch and tried to get this working. > > Problem is that the use of a resource is widely checked with "!res->flags" > throughout the code. That would have to be changed to something like > "(!res->flags || (res->flags & IORESOURCE_DISABLED))" whereever it is used. > > I tried going with "!res->flags" instead, but have not been able to get it > to work realiably; it is just very difficult to distinguish if "!res->flags" > means that the resource has not yet been assigned or if it means that it is not > supported. > > The correct approach, in my opinion, would be to go with IORESOURCE_DISABLED > and make the necessary changes whereever needed. Effectively this means to > replace the "!res->flags" check with something like pci_res_used() [ pick > your preferred name ] and define it as > > #define pci_res_used(res) ((res)->flags && !((res)->flags & IORESOURCE_DISABLED)) I think that makes sense. Maybe "res_valid()"? It's not really PCI-specific, and "used" is a little ambiguous. So is "valid", I admit. Bjorn -- 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
