| Message ID | 87v9d4gcqt.wl-kuninori.morimoto.gx@renesas.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Kieran Bingham |
| Headers | show |
| Series | [RFC] ASoC: rsnd: don't call clk_disable_unprepare() if can't use | expand |
On Tue, Dec 15, 2020 at 09:06:05AM +0900, Kuninori Morimoto wrote: > - adg->clk_rate[i] = clk_get_rate(adg->clk[i]); > + if (ret < 0) > + dev_warn(dev, "can't use clk %d\n", i); > + else > + adg->clk_rate[i] = clk_get_rate(adg->clk[i]); We never reset adg->clk_rate[i] so if we use the clock once then get an error attempting to use it again... > } else { > - clk_disable_unprepare(clk); > + if (adg->clk_rate[i]) > + clk_disable_unprepare(clk); ...we'll try to disable twice. This was already an issue of course, not something introduced in this patch.
Hi Morimoto-san, On Tue, Dec 15, 2020 at 1:06 AM Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> wrote: > We need to care clock accessibility, > because we might can't use clock for some reasons. > > It sets clk_rate for each clocks when enabled. > This means it doesn't have clk_rate if we can't use. > We can avoid to call clk_disable_unprepare() in such case. > > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Feel free to use geert+renesas@glider.be instead ;-) > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> > --- > > Hi Geert. > > Thank you for your reporting. > I have never seen this kind of error, but it possible to happen. > Unfortunately, I can't reproduce this but I hope this patch can solve it. > Could you please check this ? > I added [RFC] on this patch Subject. The patch looks good to me, but I also cannot trigger the issue at will. I went through my old boot logs, and found 2 other occurrences, also on Ebisu. In all cases, it happened while a lot of output was printed to the serial console (either a WARN() splat, or DEBUG_PINCTRL output). My guess is that console output or disabling interrupts too long is triggering a race condition or other issue in the i2c driver (clk 1 is the cs2000 clock generator, controlled through i2c). > --- a/sound/soc/sh/rcar/adg.c > +++ b/sound/soc/sh/rcar/adg.c > @@ -366,25 +366,25 @@ void rsnd_adg_clk_control(struct rsnd_priv *priv, int enable) > struct rsnd_adg *adg = rsnd_priv_to_adg(priv); > struct device *dev = rsnd_priv_to_dev(priv); > struct clk *clk; > - int i, ret; > + int i; > > for_each_rsnd_clk(clk, adg, i) { > - ret = 0; > if (enable) { > - ret = clk_prepare_enable(clk); > + int ret = clk_prepare_enable(clk); > > /* > * We shouldn't use clk_get_rate() under > * atomic context. Let's keep it when > * rsnd_adg_clk_enable() was called > */ > - adg->clk_rate[i] = clk_get_rate(adg->clk[i]); > + if (ret < 0) > + dev_warn(dev, "can't use clk %d\n", i); > + else > + adg->clk_rate[i] = clk_get_rate(adg->clk[i]); > } else { > - clk_disable_unprepare(clk); > + if (adg->clk_rate[i]) > + clk_disable_unprepare(clk); As pointed out by Mark, you may want to clear adg->clk_rate[i] here? > } > - > - if (ret < 0) > - dev_warn(dev, "can't use clk %d\n", i); > } > } With the above sorted out: Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Gr{oetje,eeting}s, Geert
Hi Geert, Mark > > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > > Feel free to use geert+renesas@glider.be instead ;-) OK, will do > The patch looks good to me, but I also cannot trigger the issue at will. > I went through my old boot logs, and found 2 other occurrences, also > on Ebisu. In all cases, it happened while a lot of output was printed to > the serial console (either a WARN() splat, or DEBUG_PINCTRL output). > My guess is that console output or disabling interrupts too long is > triggering a race condition or other issue in the i2c driver (clk 1 is the > cs2000 clock generator, controlled through i2c). OK, Thanks, nice to know. It was rare case issue, difficult to find :) > > } else { > > - clk_disable_unprepare(clk); > > + if (adg->clk_rate[i]) > > + clk_disable_unprepare(clk); > > As pointed out by Mark, you may want to clear adg->clk_rate[i] here? I thought we can re-get clock if we could get clock once. But we shouldn't assume it. Will fix it in v2. Thank you for your help !! Best regards --- Kuninori Morimoto
Hi Morimoto-san, On Thu, Dec 17, 2020 at 1:20 AM Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> wrote: > > > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > > > > Feel free to use geert+renesas@glider.be instead ;-) > > OK, will do > > > The patch looks good to me, but I also cannot trigger the issue at will. > > I went through my old boot logs, and found 2 other occurrences, also > > on Ebisu. In all cases, it happened while a lot of output was printed to > > the serial console (either a WARN() splat, or DEBUG_PINCTRL output). > > My guess is that console output or disabling interrupts too long is > > triggering a race condition or other issue in the i2c driver (clk 1 is the > > cs2000 clock generator, controlled through i2c). > > OK, Thanks, nice to know. > It was rare case issue, difficult to find :) > > > > } else { > > > - clk_disable_unprepare(clk); > > > + if (adg->clk_rate[i]) > > > + clk_disable_unprepare(clk); > > > > As pointed out by Mark, you may want to clear adg->clk_rate[i] here? > > I thought we can re-get clock if we could get clock once. Indeed. If a clock worked before, it should keep on working. However, the failing clock was the cs2000 clock, which can fail to enable if something goes wrong with i2c. Gr{oetje,eeting}s, Geert
diff --git a/sound/soc/sh/rcar/adg.c b/sound/soc/sh/rcar/adg.c index b9aacf3d3b29..b870e834aa0a 100644 --- a/sound/soc/sh/rcar/adg.c +++ b/sound/soc/sh/rcar/adg.c @@ -366,25 +366,25 @@ void rsnd_adg_clk_control(struct rsnd_priv *priv, int enable) struct rsnd_adg *adg = rsnd_priv_to_adg(priv); struct device *dev = rsnd_priv_to_dev(priv); struct clk *clk; - int i, ret; + int i; for_each_rsnd_clk(clk, adg, i) { - ret = 0; if (enable) { - ret = clk_prepare_enable(clk); + int ret = clk_prepare_enable(clk); /* * We shouldn't use clk_get_rate() under * atomic context. Let's keep it when * rsnd_adg_clk_enable() was called */ - adg->clk_rate[i] = clk_get_rate(adg->clk[i]); + if (ret < 0) + dev_warn(dev, "can't use clk %d\n", i); + else + adg->clk_rate[i] = clk_get_rate(adg->clk[i]); } else { - clk_disable_unprepare(clk); + if (adg->clk_rate[i]) + clk_disable_unprepare(clk); } - - if (ret < 0) - dev_warn(dev, "can't use clk %d\n", i); } }
We need to care clock accessibility, because we might can't use clock for some reasons. It sets clk_rate for each clocks when enabled. This means it doesn't have clk_rate if we can't use. We can avoid to call clk_disable_unprepare() in such case. Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> --- Hi Geert. Thank you for your reporting. I have never seen this kind of error, but it possible to happen. Unfortunately, I can't reproduce this but I hope this patch can solve it. Could you please check this ? I added [RFC] on this patch Subject. sound/soc/sh/rcar/adg.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)