Messages in this thread | | | From | Saravana Kannan <> | Date | Mon, 25 Jan 2021 10:16:55 -0800 | Subject | Re: [PATCH v1 5/5] driver core: Set fw_devlink=on by default |
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On Mon, Jan 25, 2021 at 9:05 AM <Tudor.Ambarus@microchip.com> wrote: > > Hi, Saravana, > > On 12/18/20 5:17 AM, Saravana Kannan wrote: > > Cyclic dependencies in some firmware was one of the last remaining > > reasons fw_devlink=on couldn't be set by default. Now that cyclic > > dependencies don't block probing, set fw_devlink=on by default. > > > > Setting fw_devlink=on by default brings a bunch of benefits (currently, > > only for systems with device tree firmware): > > * Significantly cuts down deferred probes. > > * Device probe is effectively attempted in graph order. > > * Makes it much easier to load drivers as modules without having to > > worry about functional dependencies between modules (depmod is still > > needed for symbol dependencies). > > > > If this patch prevents some devices from probing, it's very likely due > > to the system having one or more device drivers that "probe"/set up a > > device (DT node with compatible property) without creating a struct > > device for it. If we hit such cases, the device drivers need to be > > fixed so that they populate struct devices and probe them like normal > > device drivers so that the driver core is aware of the devices and their > > status. See [1] for an example of such a case. > > > > [1] - https://lore.kernel.org/lkml/CAGETcx9PiX==mLxB9PO8Myyk6u2vhPVwTMsA5NkD-ywH5xhusw@mail.gmail.com/ > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > next-20210125 fails to boot on at91 sama5d2 platforms. No output is > seen, unless earlyprintk is enabled. > > I have bisected this to commit e590474768f1cc04 ("driver core: Set > fw_devlink=on by default"). > > I've attached a log that I'm seeing on a sama5d2_xplained (sama5_defconfig > and arch/arm/boot/dts/at91-sama5d2_xplained.dts). I enabled the > following logs: > 1. The ones in device_links_check_suppliers() > 2. The ones in device_link_add() > 3. initcall_debug=1 > > There seem to be some probe fails due to the pmc supplier not being ready: > calling at_xdmac_init+0x0/0x18 @ 1 > platform f0010000.dma-controller: probe deferral - supplier f0014000.pmc not ready > platform f0004000.dma-controller: probe deferral - supplier f0014000.pmc not ready > initcall at_xdmac_init+0x0/0x18 returned -19 after 19531 usecs > > calling udc_driver_init+0x0/0x18 @ 1 > platform 300000.gadget: probe deferral - supplier f0014000.pmc not ready > initcall udc_driver_init+0x0/0x18 returned -19 after 7524 usecs > > There are others too. I'm checking them.
Thanks Tudor. I'll look into this within a few days. I'm also looking into coming up with a more generic solution.
-Saravana
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