On Sun, May 13, 2012 at 6:55 PM, Richard Yang <weiyang@xxxxxxxxxxxxxxxxxx> wrote: > On Mon, Apr 23, 2012 at 03:46:03PM -0400, Don Dutile wrote: >>On 04/22/2012 11:52 AM, Richard Yang wrote: >>>All, >>> >>>I am reading the pci_scan_bridge() and not sure what will happen in >>>following situation. >>> >>>Suppose the kernel is not passed the pci=assign-busses. >>> >>>Below is a picture about the pci system. >>> >>> +-------+ >>> | | root bridge(0,255) >>> +---+---+ >>> | Bus 0 >>> -----+-----------+------------------------------+-- >>> | | >>> | | >>> | | >>> +----+----+ +-----+-----+ >>> | | B1(1,15) | |B2(16,28) >>> +----+----+ +-----+-----+ >>> | Bus 1 | Bus 16 >>> -----+----------------------- ----------+---------------- >>> | >>> +----+----+ >>> | | B3 >>> +---------+ >>> >>>Suppose B1 and B2 works fine with the BIOS, which get the right bus >>>number and range. >>> >>>B3 does not works fine with the BIOS, which doesn't get the bus number. >>> >>>So in pci_scan_bridge(), B3 will be met in the second pass and get bus >>>number 16? >> > Yinghai, > > Take my original question. > > B3 doesn't get the bus number, which its parent doesn't have free bus > number and there is no gap between B1 and B2. > > So in this case, the probe_resource() can't find bus number for B3. > Then cause pci_bridge_probe_busn_res() return non-zero. > > Then B3 couldn't work fine? B3 is on Bus 1? B3 is the one of bridges on Bus1? if B3 is only bridge on Bus1, it probe_resource should return [2,15] at first, and then scan B3. Yinghai -- 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
