Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Wed, 19 May 2021 20:17:16 +0200 | Subject | Re: [PATCH v7 0/5] clk: add driver for the SiFive FU740 |
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Hi Zong,
On Wed, May 19, 2021 at 5:55 PM Zong Li <zong.li@sifive.com> wrote: > On Tue, May 11, 2021 at 4:57 PM Yixun Lan <yixun.lan@gmail.com> wrote: > > On Wed, Apr 14, 2021 at 2:25 PM Zong Li <zong.li@sifive.com> wrote: > > > On Mon, Apr 12, 2021 at 7:31 PM Andreas Schwab <schwab@linux-m68k.org> wrote: > > > > On Mär 31 2021, Zong Li wrote: > > > > > I found that the gemgxlpll was disabled immediately by power > > > > > management after macb driver install. The mainline's defconfig doesn't > > > > > enable CONFIG_PM, so the network is fine on it. The opensuse defconfig > > > > > enables CONFIG_PM, and the patch > > > > > 732374a0b440d9a79c8412f318a25cd37ba6f4e2 added the enable/disable > > > > > callback functions, so the gemgxlpll PLL, I have no idea why power > > > > > management disable it, I would keep trace it. > > > > > > > > Does that mean that CONFIG_PM also affects the FU740? > > > > > > Yes, we got the same problem on the FU740. We are checking the issue. > > > > > Just a mild ping, any progress regarding this issue? > > Currently, if runtime power management is enabled, macb driver would > go to sleep at the end of macb_probe, then the gigabit ethernet PLL > would be disabled. During this period of time, the system would hang > up if we try to access GEMGXL control registers, it means that we > can't access GEMGXL control registers before the gigabit ethernet PLL > is resumed again. There are some cases, for example, if we execute the
Sounds familiar.
> 'ifconfig' command, it would eventually go to the macb_get_status to
Do you mean mac_get_stats()? macb_get_status() does not exist.
> access GEMGXL control registers and cause the system to hang up. Give > more example here, if we execute 'ip link set lo up & ip addr add > 127.0.0.1/8 dev lo', it would cause the system to hang up, because > these commands would try to query the interfaces and eventually go to > macb_get_status as well. However, if we can resume the gigabit > ethernet PLL first, such as 'ip link set eth0 up' or 'udhcpc', then > everything goes well. I'm trying to figure out if there are some hooks > that we can check the PLL status in the macb driver before it actually > touches the control registers. If anyone has an idea about that, > please feel free to point it out to me, thanks.
And you cannot call pm_runtime_get_sync(), as this is called from atomic contect. Other drivers avoid accessing the registers while the device is not up, cfr. e.g. commit 7fa2955ff70ce453 ("sh_eth: Fix sleeping function called from invalid context").
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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