Hello Johannes,
thanks for your patch.
While it works well in my lab setting, it crashes within minutes in the field.
While the crashes look slightly different ("Unable to handle kernel pagign request"... descendant of is_swiotlb_active...) I think the notice beforehand is much more interesting: do you understand it?
: ------------[ cut here ]------------
: Voluntary context switch within RCU read-side critical section!
: WARNING: CPU: 0 PID: 319 at kernel/rcu/tree_plugin.h:320 rcu_note_context_switch+0x484/0x550
: Modules linked in: ov9281 rtc_pcf85063 regmap_i2c brcmfmac brcmutil v3d gpu_sched drm_shmem_helper cfg80211 gpio_keys i2c_mux_pinctrl i2c_mux vc4 rfkill raspberrypi_hwmon bcm2835_codec(C) bcm2835_v4l2(C) bcm2835_isp(C) bcm2835_unicam snd_soc_hdmi_codec v4l2_dv_timings bcm2835_mmal_vchiq(C) drm_display_helper rpivid_hevc(C) v4l2_fwnode v4l2_mem2mem videobuf2_vmalloc cec v4l2_async videobuf2_dma_contig i2c_brcmstb videobuf2_memops drm_dma_helper videobuf2_v4l2 i2c_bcm2835 drm_kms_helper snd_soc_core videobuf2_common videodev vc_sm_cma(C) snd_bcm2835(C) snd_compress snd_pcm_dmaengine snd_pcm snd_timer mc snd syscopyarea sysfillrect sysimgblt fb_sys_fops uio_pdrv_genirq nvmem_rmem uio drm drm_panel_orientation_quirks fuse backlight ip_tables x_tables ipv6
: CPU: 0 PID: 319 Comm: kworker/0:3 Tainted: G C 6.1.45-v8-ged6bf58272ec #2
: Hardware name: Raspberry Pi Compute Module 4 Rev 1.0 (DT)
: Workqueue: events brcmf_fweh_event_worker [brcmfmac]
: pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
: pc : rcu_note_context_switch+0x484/0x550
: lr : rcu_note_context_switch+0x484/0x550
: sp : ffffffc008d337c0
: x29: ffffffc008d337c0 x28: ffffff804765be00 x27: 000000000000001b
: x26: 0000000000000001 x25: 0000000000000000 x24: ffffff804765be00
: x23: ffffff804765be00 x22: 0000000000000000 x21: 0000000000000000
: x20: ffffffdcc58f4f00 x19: ffffff807fb5ff00 x18: 00000000fffffffc
: x17: 2e2e2e2e2e202020 x16: ffffffdcc53b9bb0 x15: 0000000000000020
: x14: ffffffdcc5c65358 x13: 216e6f6974636573 x12: 206c616369746972
: x11: 00000000000021c8 x10: 0000000000002180 x9 : ffffffdcc48fc5c4
: x8 : ffffffdcc5c0c788 x7 : ffffffdcc5c64788 x6 : 0000000000005538
: x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000027
: x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffffff804765be00
: Call trace:
: rcu_note_context_switch+0x484/0x550
: __schedule+0xc0/0xa10
: schedule+0x60/0x100
: schedule_timeout+0xa0/0x1c0
: brcmf_sdio_bus_txctl+0xcc/0x1f4 [brcmfmac]
: brcmf_proto_bcdc_msg+0xd4/0xf0 [brcmfmac]
: brcmf_proto_bcdc_set_dcmd+0x88/0x124 [brcmfmac]
: brcmf_fil_cmd_data+0x84/0x180 [brcmfmac]
: brcmf_fil_iovar_data_set+0x11c/0x160 [brcmfmac]
: brcmf_cfg80211_set_cqm_rssi_range_config+0xe4/0x130 [brcmfmac]
: cfg80211_cqm_rssi_update+0x120/0x3f0 [cfg80211]
: cfg80211_cqm_rssi_notify+0x78/0x1b4 [cfg80211]
: brcmf_notify_rssi+0x10c/0x1b0 [brcmfmac]
: brcmf_fweh_call_event_handler+0x40/0xa0 [brcmfmac]
: brcmf_fweh_event_worker+0x1e4/0x4e0 [brcmfmac]
: process_one_work+0x1dc/0x450
: worker_thread+0x154/0x450
: kthread+0x104/0x110
: ret_from_fork+0x10/0x20
: ---[ end trace 0000000000000000 ]---
