Hi, 在 2025-05-22 16:45:08，"Krzysztof Kozlowski" <k...@kernel.org> 写道： >On 16/05/2025 11:58, Heiko Stübner wrote: >> Am Donnerstag, 15. Mai 2025, 17:54:20 Mitteleuropäische Sommerzeit schrieb >> Krzysztof Kozlowski: >>> On 15/05/2025 14:35, long.yunj...@zte.com.cn wrote: >>>> From: Yumeng Fang <fang.yum...@zte.com.cn> >>>> >>>> In the probe path, dev_err() can be replaced with dev_err_probe() >>> >>> That's not probe path. I am not sure if you really understand this code. >> >> I think that is somewhat debateable. >> >> dw_hdmi_rockchip_bind() is part of the rockchip-drm component device, >> so part of its probe-path. Also I think just the presence of EPROBE_DEFER >> which causes the device to re-try probing later is a nice indicator that the > >No, that's not true. You can call every API like regulator_get from any >context and you will get EPROBE_DEFER. This will not be a probe path. >There are multiple cases of such drivers, I saw such patch even day ago. > >> code in question is _a_ probe path. (and usage of EPROBE_DEFER is an >> established pattern to make that component device re-try probing later) >> >> And the parse_dt function itself is part of that path too. > >I quickly glanced and this was not obvious. The commit msg is poor here >and does not explain that component_bind is ALWAYS probe path (unless it >is clear for DRM folks).
Yes, the component_bind is called in the probe path, here is one dump stack: [ 1.113096] platform fdd90000.vop: Adding to iommu group 8 [ 1.120336] rockchip-drm display-subsystem: bound fdd90000.vop (ops vop2_component_ops) [ 1.121543] rockchip-drm display-subsystem: bound fde50000.dp (ops dw_dp_rockchip_component_ops) [ 1.122834] dwhdmiqp-rockchip fde80000.hdmi: registered DesignWare HDMI QP I2C bus driver [ 1.123554] CPU: 5 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.15.0-rc5+ #667 PREEMPT [ 1.123561] Hardware name: RK3588S CoolPi 4 Model B (DT) [ 1.123565] Call trace: [ 1.123567] show_stack+0x18/0x24 (C) [ 1.123577] dump_stack_lvl+0x74/0x8c [ 1.123584] dump_stack+0x18/0x24 [ 1.123589] dw_hdmi_qp_rockchip_bind+0x2f8/0x468 [ 1.123601] component_bind_all+0x120/0x278 [ 1.123611] rockchip_drm_bind+0x9c/0x1ac [ 1.123616] try_to_bring_up_aggregate_device+0x214/0x2d8 [ 1.123625] component_master_add_with_match+0xc4/0x104 [ 1.123635] rockchip_drm_platform_probe+0x214/0x33c [ 1.123640] platform_probe+0x68/0xc8 [ 1.123646] really_probe+0xc0/0x390 [ 1.123655] __driver_probe_device+0x7c/0x15c [ 1.123663] driver_probe_device+0x3c/0x110 [ 1.123671] __driver_attach+0xf0/0x1f8 [ 1.123679] bus_for_each_dev+0x7c/0xe0 [ 1.123686] driver_attach+0x24/0x30 > > >Best regards, >Krzysztof
