[PATCH] net: stmmac:fix system hang when setting up standalone tag_8021q VLAN for DSA ports

[Jakub Kicinski]

On Sat,  8 Apr 2023 23:58:23 +0800 Yan Wang wrote:
> The system hang because of dsa_tag_8021q_port_setup() callbcak
> stmmac_vlan_rx_add_vid().I found in stmmac_drv_probe() that
> cailing pm_runtime_put() disabled the clock when check the stmmac
> dirver.
> 
> First, when the kernel is compiled with CONFIG_PM=y,The stmmac's
> resume/suspend is active.
> 
> Secondly,stmmac as DSA master,the dsa_tag_8021q_port_setup() function
> will callback stmmac_vlan_rx_add_vid when DSA dirver starts. However,
> The system is hanged for the stmmac_vlan_rx_add_vid() accesses its
> registers after stmmac's clock is closed.
> 
> I would suggest adding the pm_runtime_resume_and_get() to the
> stmmac_vlan_rx_add_vid().This guarantees that resuming clock output
> while in use.

Hm, the patch is not making it to the @vger list, even tho it did make
it to lore.kernel.org, it seems. I couldn't spot anything wrong with it.
Could you try sending it to testing at vger.kernel.org and contacting
John (added to CC) who administers vger.kernel.org, to figure out
what's wrong?

Based on this conversation:
https://lore.kernel.org/all/9539b880-642d-9ac5-ccfa-2b237548f4fc@kernel.org/