From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomeu Vizoso Subject: Re: [PATCH v6 22/22] of/platform: Defer probes of registered devices Date: Thu, 22 Oct 2015 15:04:59 +0200 Message-ID: References: <1442844182-27787-1-git-send-email-tomeu.vizoso@collabora.com> <1442844182-27787-23-git-send-email-tomeu.vizoso@collabora.com> <1445406845.701.55.camel@freescale.com> <1445467912.701.90.camel@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <1445467912.701.90.camel-KZfg59tc24xl57MIdRCFDg@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Scott Wood Cc: Rob Herring , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Stephen Warren , Javier Martinez Canillas , Greg Kroah-Hartman , Mark Brown , Thierry Reding , Alan Stern , "Rafael J. Wysocki" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Dmitry Torokhov , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Linus Walleij , "linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Arnd Bergmann , linuxppc-dev , Hu Mingkai-B21284 List-Id: devicetree@vger.kernel.org On 22 October 2015 at 00:51, Scott Wood wrote: > On Wed, 2015-10-21 at 08:44 -0500, Rob Herring wrote: >> On Wed, Oct 21, 2015 at 12:54 AM, Scott Wood >> 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 >> > > --- >> > > >> > > 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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > 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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html