Hi, Saravana, On 1/25/21 8:16 PM, Saravana Kannan wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the > content is safe > > On Mon, Jan 25, 2021 at 9:05 AM <tudor.amba...@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-ywh5xh...@mail.gmail.com/ >>> Signed-off-by: Saravana Kannan <sarava...@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. >
I've sent a patch addressing this at: https://lore.kernel.org/lkml/20210128104446.164269-1-tudor.amba...@microchip.com/T/#u Can you please take a look? Cheers, ta
