Messages in this thread | | | Date | Sat, 30 Jul 2022 22:30:36 +0200 | Subject | Re: [PATCH 1/2] stmmac: intel: Add a missing clk_disable_unprepare() call in intel_eth_pci_remove() | From | Christophe JAILLET <> |
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Le 30/07/2022 à 22:17, Andy Shevchenko a écrit : > On Sat, Jul 30, 2022 at 08:19:47PM +0200, Christophe JAILLET wrote: >> Commit 09f012e64e4b ("stmmac: intel: Fix clock handling on error and remove >> paths") removed this clk_disable_unprepare() >> >> This was partly revert by commit ac322f86b56c ("net: stmmac: Fix clock >> handling on remove path") which removed this clk_disable_unprepare() >> because: >> " >> While unloading the dwmac-intel driver, clk_disable_unprepare() is >> being called twice in stmmac_dvr_remove() and >> intel_eth_pci_remove(). This causes kernel panic on the second call. >> " >> >> However later on, commit 5ec55823438e8 ("net: stmmac: add clocks management >> for gmac driver") has updated stmmac_dvr_remove() which do not call >> clk_disable_unprepare() anymore. >> >> So this call should now be called from intel_eth_pci_remove(). > > The correct way of fixing it (which might be very well end up functionally > the same as this patch), is to introduce ->quit() in struct stmmac_pci_info > and assign it correctly, because not all platforms enable clocks.
I won't be able to propose anything like that.
By the way, in the first sentence of my log, s/removed/added/. (I hope that it can be fixed when/if the patch is applied)
Thanks for the review.
CJ
> > Perhaps, we may leave this patch as is (for the sake of easy backporting) and > apply another one as I explained above to avoid similar mistakes in the future. > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > >> Fixes: 5ec55823438e8 ("net: stmmac: add clocks management for gmac driver") >> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> >> --- >> /!\ This patch is HIGHLY speculative. /!\ >> >> The corresponding clk_disable_unprepare() is still called within the pm >> related stmmac_bus_clks_config() function. >> >> However, with my limited understanding of the pm API, I think it that the >> patch is valid. >> (in other word, does the pm_runtime_put() and/or pm_runtime_disable() >> and/or stmmac_dvr_remove() can end up calling .runtime_suspend()) >> >> So please review with care, as I'm not able to test the change by myself. >> >> >> If I'm wrong, maybe a comment explaining why it is safe to have this >> call in the error handling path of the probe and not in the remove function >> would avoid erroneous patches generated from static code analyzer to be >> sent. >> --- >> drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c >> index 52f9ed8db9c9..9f38642f86ce 100644 >> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c >> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c >> @@ -1134,6 +1134,7 @@ static void intel_eth_pci_remove(struct pci_dev *pdev) >> >> stmmac_dvr_remove(&pdev->dev); >> >> + clk_disable_unprepare(plat->stmmac_clk); >> clk_unregister_fixed_rate(priv->plat->stmmac_clk); >> >> pcim_iounmap_regions(pdev, BIT(0)); >> -- >> 2.34.1 >> >
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