On 22 October 2015 at 00:51, Scott Wood <scottwood@xxxxxxxxxxxxx> wrote: > On Wed, 2015-10-21 at 08:44 -0500, Rob Herring wrote: >> On Wed, Oct 21, 2015 at 12:54 AM, Scott Wood <scottwood@xxxxxxxxxxxxx> >> wrote: >> > On Mon, 2015-09-21 at 16:03 +0200, Tomeu Vizoso wrote: >> > > Instead of trying to match and probe platform and AMBA devices right >> > > after each is registered, delay their probes until device_initcall_sync. >> > > >> > > This means that devices will start probing once all built-in drivers >> > > have registered, and after all platform and AMBA devices from the DT >> > > have been registered already. >> > > >> > > This allows us to prevent deferred probes by probing dependencies on >> > > demand. >> > > >> > > Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx> >> > > --- >> > > >> > > Changes in v4: >> > > - Also defer probes of AMBA devices registered from the DT as they can >> > > also request resources. >> > > >> > > drivers/of/platform.c | 11 ++++++++--- >> > > 1 file changed, 8 insertions(+), 3 deletions(-) >> > >> > This breaks arch/powerpc/sysdev/fsl_pci.c. The PCI bus is an OF platform >> > device, and it must be probed before pcibios_init() which is a >> > subsys_initcall(), or else the PCI bus never gets scanned. >> >> Thanks for the report. This is probably getting dropped, but it could >> be disabled for PPC. > > I don't think that adding another arbitrary arch difference would be the > right solution. I think Rob meant temporarily disable it while things get fixed. At least, I don't see any reason why PPC wouldn't benefit from this series. Regards, Tomeu >> Any plans to fix this and make PCI hosts hotplugable? For the scanning >> part, generally the host controller drivers are responsible for >> scanning their bus now. > > Scanning from the host controller driver seems like a reasonable goal, though > > it'd take a bit of digging to extract whatever other things fsl_pci may > depend on from the common PPC PCI code, in particular the various things that > > pcibios_resource_survey() does after all PCI buses have been scanned. > > There's also check_swiotlb_enabled(), another subsys_initcall, which frees > the swiotlb memory if ppc_swiotlb_enable hasn't been set. The PCI host > controller probe sets ppc_swiotlb_enable if it wasn't able to create an > inbound mapping for all RAM. Even if we were to change that to a later > initcall, there's nothing later than late_initcall that we could use. > > -Scott > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
