On Thu, Jan 28, 2021 at 2:59 AM <tudor.amba...@microchip.com> wrote: > > 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?
Thanks for taking a look at this. I responded in that thread. -Saravana
