On 21-11-16 17:11:33, Abel Vesa wrote: > On 21-11-16 15:59:11, Abel Vesa wrote: > > On 21-11-15 12:17:46, Saravana Kannan wrote: > > > On Wed, Nov 10, 2021 at 12:24 PM Saravana Kannan <saravanak@xxxxxxxxxx> wrote: > > > > > > > > On Wed, Nov 10, 2021 at 4:16 AM Abel Vesa <abelvesa@xxxxxxxxxx> wrote: > > > > > > > > > > On 21-09-28 17:07:33, Saravana Kannan wrote: > > > > > > fw_devlink could end up creating device links for bus only devices. > > > > > > However, bus only devices don't get probed and can block probe() or > > > > > > sync_state() [1] call backs of other devices. To avoid this, probe these > > > > > > devices using the simple-pm-bus driver. > > > > > > > > > > > > However, there are instances of devices that are not simple buses (they get > > > > > > probed by their specific drivers) that also list the "simple-bus" (or other > > > > > > bus only compatible strings) in their compatible property to automatically > > > > > > populate their child devices. We still want these devices to get probed by > > > > > > their specific drivers. So, we make sure this driver only probes devices > > > > > > that are only buses. > > > > > > > > > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@xxxxxxxxxxxxxx/ > > > > > > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > > > > > > Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx> > > > > > > Tested-by: Saravana Kannan <saravanak@xxxxxxxxxx> > > > > > > Tested-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > > > > > --- > > > > > > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > > > > > > 1 file changed, 39 insertions(+), 3 deletions(-) > > > > > > > > > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > > > > > index 01a3d0cd08ed..6b8d6257ed8a 100644 > > > > > > --- a/drivers/bus/simple-pm-bus.c > > > > > > +++ b/drivers/bus/simple-pm-bus.c > > > > > > @@ -13,11 +13,36 @@ > > > > > > #include <linux/platform_device.h> > > > > > > #include <linux/pm_runtime.h> > > > > > > > > > > > > - > > > > > > static int simple_pm_bus_probe(struct platform_device *pdev) > > > > > > { > > > > > > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > > > > > > - struct device_node *np = pdev->dev.of_node; > > > > > > + const struct device *dev = &pdev->dev; > > > > > > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > > > > > > + struct device_node *np = dev->of_node; > > > > > > + const struct of_device_id *match; > > > > > > + > > > > > > + /* > > > > > > + * Allow user to use driver_override to bind this driver to a > > > > > > + * transparent bus device which has a different compatible string > > > > > > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > > > > > > + * of the simple-pm-bus tasks for these devices, so return early. > > > > > > + */ > > > > > > + if (pdev->driver_override) > > > > > > + return 0; > > > > > > + > > > > > > + match = of_match_device(dev->driver->of_match_table, dev); > > > > > > + /* > > > > > > + * These are transparent bus devices (not simple-pm-bus matches) that > > > > > > + * have their child nodes populated automatically. So, don't need to > > > > > > + * do anything more. We only match with the device if this driver is > > > > > > + * the most specific match because we don't want to incorrectly bind to > > > > > > + * a device that has a more specific driver. > > > > > > + */ > > > > > > + if (match && match->data) { > > > > > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > > > > > > + return 0; > > > > > > + else > > > > > > + return -ENODEV; > > > > > > + } > > > > > > > > > > This change is breaking the expected behavior for the already existent > > > > > simple-bus nodes. All the simple-bus compatibles should be replaced now > > > > > to simple-pm-bus. In my case, on some i.MX8 platforms, without the > > > > > devlink, the devices suspend sequence changes (and even breaks). > > > > > > > > > > To avoid breaking the already existent simple-bus nodes, maybe the logic > > > > > should've been reversed: keep the simple-bus as is and add another > > > > > compatible, IDK, something like simple-trasnparent-bus, or something. > > > > > > > > The intent of this change IS to affect existing simple-bus nodes (but > > > > not in the way it's affecting you). But if it's breaking stuff, we > > > > obviously need to fix it. > > > > > > > > I have a hunch on what's going on in your case, but can you point me > > > > to the specific simple-bus node that's getting affected? I'm expecting > > > > it to be a simple-bus node that gets added AFTER this driver is > > > > registered at device_initcall (module_init gets converted to > > > > device_initcall). > > > > > > > > Well, for now, I can't pinpoint exactly one specific dts node. > > My usecase is a little bit more complicated since it's only happening > > in conjunction with a local change in the imx-mu-irq driver > > in our local tree. Basically, the local change is forcing a suspend abort by > > calling pm_system_wake if there is an irq from SCU triggered after the > > suspend noirq imx-mu-irq driver callback has been called. > > If we replace all the simple-bus with simple-pm-bus, everything works > > fine. > > > > > > Also, can you try this hack patch to see if it helps your case? > > > > https://lore.kernel.org/lkml/CAGETcx9U130Oq-umrvXME4JhEpO0Wadoki3kNxx=0-YvTR6PtQ@xxxxxxxxxxxxxx/ > > > > > > > > Nope, it doesn't work with this patch either. > > > > And the funny thing is, even if I add the pm_runtime_enable to your patch > > like this: > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > index 6b8d6257ed8a..a13324fd700b 100644 > > --- a/drivers/bus/simple-pm-bus.c > > +++ b/drivers/bus/simple-pm-bus.c > > @@ -38,9 +38,11 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > > * a device that has a more specific driver. > > */ > > if (match && match->data) { > > - if (of_property_match_string(np, "compatible", match->compatible) == 0) > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) { > > + pm_runtime_enable(&pdev->dev); > > + of_platform_populate(np, NULL, lookup, &pdev->dev); > > return 0; > > - else > > + } else > > return -ENODEV; > > } > > > > I get the following warning: > > > > [ 1.009392] ------------[ cut here ]------------ > > [ 1.013681] Enabling runtime PM for inactive device (bus@5d000000) with active children > > [ 1.021721] WARNING: CPU: 3 PID: 1 at drivers/base/power/runtime.c:1439 pm_runtime_enable+0xc0/0x100 > > [ 1.030794] Modules linked in: > > [ 1.033837] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.15.0-04906-gc0a8c67532b6-dirty #226 > > [ 1.042175] Hardware name: Freescale i.MX8QXP MEK (DT) > > [ 1.047302] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) > > [ 1.054248] pc : pm_runtime_enable+0xc0/0x100 > > [ 1.058594] lr : pm_runtime_enable+0xc0/0x100 > > [ 1.062938] sp : ffff800011e4bb60 > > [ 1.066237] x29: ffff800011e4bb60 x28: 0000000000000000 x27: ffff8000119204d0 > > [ 1.073361] x26: ffff8000119c1060 x25: ffff8000119c1078 x24: ffff80001190f0a0 > > [ 1.080484] x23: 0000000000000000 x22: 0000000000000000 x21: ffff0008006a00f4 > > [ 1.087608] x20: 0000000000000000 x19: ffff0008006a0010 x18: 0000000000000030 > > [ 1.094732] x17: 6974636120687469 x16: 7720293030303030 x15: 3064354073756228 > > [ 1.101856] x14: 2065636976656420 x13: ffff800011c21dc0 x12: 0000000000000246 > > [ 1.108981] x11: 00000000000000c2 x10: ffff800011c79dc0 x9 : 00000000fffff000 > > [ 1.116103] x8 : ffff800011c21dc0 x7 : ffff800011c79dc0 x6 : 0000000000000000 > > [ 1.123227] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 00000000ffffefff > > [ 1.130351] x2 : ffff800011c21d30 x1 : 6bf7c63081c63600 x0 : 0000000000000000 > > [ 1.137478] Call trace: > > [ 1.139910] pm_runtime_enable+0xc0/0x100 > > [ 1.143903] simple_pm_bus_probe+0x80/0xf0 > > [ 1.147986] platform_probe+0x6c/0xe0 > > [ 1.151637] really_probe.part.0+0x9c/0x310 > > [ 1.155805] __driver_probe_device+0x98/0x144 > > [ 1.160149] driver_probe_device+0xc8/0x15c > > [ 1.164319] __driver_attach+0xfc/0x190 > > [ 1.168141] bus_for_each_dev+0x70/0xc0 > > [ 1.171964] driver_attach+0x28/0x3c > > [ 1.175526] bus_add_driver+0x108/0x1f0 > > [ 1.179348] driver_register+0x7c/0x130 > > [ 1.183173] __platform_driver_register+0x2c/0x40 > > [ 1.187862] simple_pm_bus_driver_init+0x20/0x2c > > [ 1.192466] do_one_initcall+0x54/0x1bc > > [ 1.196289] kernel_init_freeable+0x210/0x294 > > [ 1.200633] kernel_init+0x28/0x130 > > [ 1.204110] ret_from_fork+0x10/0x20 > > [ 1.207678] ---[ end trace 719a02e69bfeb03f ]--- > > > > though it should be behaving exactly like in the case of simple-pm-bus. > > > > Maybe I'm missing something here. > > > > I'll keep digging. > > Looking at this, it seems the devlinks are actually dropped after being created: [ 36.993371] Hardware name: Freescale i.MX8QXP MEK (DT) [ 36.998498] Call trace: [ 37.000928] dump_backtrace+0x0/0x19c [ 37.004578] show_stack+0x1c/0x70 [ 37.007878] dump_stack_lvl+0x68/0x84 [ 37.011527] dump_stack+0x1c/0x38 [ 37.014826] __device_link_del+0x40/0xbc [ 37.018738] device_link_drop_managed+0x74/0x90 [ 37.023253] device_links_driver_bound+0x1b4/0x280 [ 37.028031] driver_bound+0x68/0xd0 [ 37.031509] really_probe.part.0+0x258/0x310 [ 37.035763] __driver_probe_device+0x98/0x144 [ 37.040107] driver_probe_device+0xc8/0x15c [ 37.044279] __driver_attach+0xfc/0x190 [ 37.048100] bus_for_each_dev+0x70/0xc0 [ 37.051924] driver_attach+0x28/0x3c [ 37.055484] bus_add_driver+0x108/0x1f0 [ 37.059306] driver_register+0x7c/0x130 [ 37.063131] __platform_driver_register+0x2c/0x40 [ 37.067820] simple_pm_bus_driver_init+0x20/0x2c [ 37.072424] do_one_initcall+0x54/0x1bc [ 37.076249] kernel_init_freeable+0x210/0x294 [ 37.080591] kernel_init+0x28/0x130 [ 37.084068] ret_from_fork+0x10/0x20 [ 37.087688] simple-pm-bus bus@56220000: Dropping the link to 5d090000.gpio [ 37.094501] device: 'platform:5d090000.gpio--platform:bus@56220000': device_unregister So, before your patch, the devlinks were not dropped because there was no driver to probe for the "simple-bus" compatible. And I think this tells us why your hack patch didn't solve the problem either. > > One more thing. > > So basically, your already upstream patch removes the devlinks for all the simple-bus > nodes. > > By adding your hack patch, it also removes devlinks between subnodes of the simple-bus > node. > > > > > I have some thoughts on how I could fix this, but I need to think > > > > about a few cases. > > > > > > Hi Abel, > > > > > > Friendly reminder. > > > > > > > Sorry for the late reply. > > > > > -Saravana
