Re: [PATCH net-next v4] net: stmmac:fix system hang when setting up tag_8021q VLAN for DSA ports

[Florian Fainelli]

On 4/13/23 10:07, Jacob Keller wrote:
> On 4/13/2023 8:06 AM, Yan Wang wrote:
> > The system hang because of dsa_tag_8021q_port_setup()->
> > 				stmmac_vlan_rx_add_vid().
> >
> > I found in stmmac_drv_probe() that cailing pm_runtime_put()
> > disabled the clock.
> >
> > 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.
> >
> > Signed-off-by: Yan Wang <rk.code@xxxxxxxxxxx>
>
> This looks identical to the net fix you posted at [1]. I don't think we
> need both?
>
> [1]:
> https://lore.kernel.org/netdev/KL1PR01MB5448020DE191340AE64530B0E6989@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/

Unfortunately both still lack a proper Fixes: tag, and this is bug fix.
--
Florian