Den 07.09.2022 11.58, skrev Maxime Ripard: > On Mon, Sep 05, 2022 at 05:17:18PM +0200, Noralf Trønnes wrote: >> Den 05.09.2022 16.57, skrev Maxime Ripard: >>> 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. >>> >> >> The first thing I tried was to unload the bcm2711_thermal module before >> running modeset and it still hung, so I don't think that's the problem. > > Ack. Just to confirm, is this happening on mainline or on the downstream tree? > It's mainline. Noralf.
