Hello Mark, On Thu, 9 Jan 2020 20:38:19 +0000, Mark Brown <broonie@xxxxxxxxxx> wrote: > On Fri, Dec 27, 2019 at 04:20:56PM +0100, Peter Seiderer wrote: > > @@ -338,7 +338,8 @@ static unsigned long clk_aic32x4_div_recalc_rate(struct clk_hw *hw, > > > unsigned int val; > > > - regmap_read(div->regmap, div->reg, &val); > > + if (regmap_read(div->regmap, div->reg, &val)) Unrelated to your question, but I would change this line (on next patch iteration) to (as all other return value checked places for regmap_read in the same file): if (regmap_read(div->regmap, div->reg, &val) < 0) > > + return 0; > > Is this the best fix - shouldn't we be returning an error here? We > don't know what the value programmed into the device actually is so zero > might be wrong, and we still have the risk that the value we read from > the device may be zero if the device is misprogrammed. clk_aic32x4_div_recalc_rate() is used for clk_ops aic32x4_div_ops.recalc_rate, did not check/or see on first sight if there is a error handling on the usage of recalc_rate, but did take a look at some other places where the error handling seems to be to return zero, e.g. sound/soc/codecs/da7219.c sound/soc/intel/skylake/skl-ssp-clk.c, etc. The error occurred with linux-5.3.18, with the earlier versions on regmap_read failure val was (by chance) near 2^31 and evaluated with (val & AIC32X4_DIV_MASK) to 96 (or similar)...but with 5.3.18 evaluated to 0 and the line return DIV_ROUND_UP(parent_rate, val & AIC32X4_DIV_MASK); produced the 'Division by zero'... Regards, Peter _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
