On Fri, Sep 02, 2022 at 01:28:16PM +0200, Noralf Trønnes wrote: > > > Den 01.09.2022 21.35, skrev Noralf Trønnes: > > > > > > I have finally found a workaround for my kernel hangs. > > > > Dom had a look at my kernel and found that the VideoCore was fine, and > > he said this: > > > >> That suggests cause of lockup was on arm side rather than VC side. > >> > >> But it's hard to diagnose further. Once you've had a peripheral not > >> respond, the AXI bus locks up and no further operations are possible. > >> Usual causes of this are required clocks being stopped or domains > >> disabled and then trying to access the hardware. > >> > > > > So when I got this on my 64-bit build: > > > > [ 166.702171] SError Interrupt on CPU1, code 0x00000000bf000002 -- SError > > [ 166.702187] CPU: 1 PID: 8 Comm: kworker/u8:0 Tainted: G W > > 5.19.0-rc6-00096-gba7973977976-dirty #1 > > [ 166.702200] Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT) > > [ 166.702206] Workqueue: events_freezable_power_ thermal_zone_device_check > > [ 166.702231] pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS > > BTYPE=--) > > [ 166.702242] pc : regmap_mmio_read32le+0x10/0x28 > > [ 166.702261] lr : regmap_mmio_read+0x44/0x70 > > ... > > [ 166.702606] bcm2711_get_temp+0x58/0xb0 [bcm2711_thermal] > > > > I wondered if that reg read was stalled due to a clock being stopped. > > > > Lo and behold, disabling runtime pm and keeping the vec clock running > > all the time fixed it[1]. > > > > I don't know what the problem is, but at least I can now test this patchset. > > > > [1] https://gist.github.com/notro/23b984e7fa05cfbda2db50a421cac065 > > > > It turns out I didn't have to disable runtime pm: > https://gist.github.com/notro/0adcfcb12460b54e54458afe11dc8ea2 If the bcm2711_thermal IP needs that clock to be enabled, it should grab a reference itself, but it looks like even the device tree binding doesn't ask for one. Maxime
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