Messages in this thread | | | Subject | Re: [PATCH] memory: samsung: exynos5422-dmc: propagate error from exynos5_counters_get() | From | Lukasz Luba <> | Date | Tue, 4 Aug 2020 10:11:03 +0100 |
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Hi Marek,
On 8/4/20 7:12 AM, Marek Szyprowski wrote: > exynos5_counters_get() might fail with -EPROBE_DEFER if the driver for > devfreq event counter is not yet probed. Propagate that error value to > the caller to ensure that the exynos5422-dmc driver will be probed again > when devfreq event contuner is available. > > This fixes boot hang if both exynos5422-dmc and exynos-ppmu drivers are > compiled as modules. > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > --- > drivers/memory/samsung/exynos5422-dmc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c > index b9c7956e5031..639811a3eecb 100644 > --- a/drivers/memory/samsung/exynos5422-dmc.c > +++ b/drivers/memory/samsung/exynos5422-dmc.c > @@ -914,7 +914,7 @@ static int exynos5_dmc_get_status(struct device *dev, > } else { > ret = exynos5_counters_get(dmc, &load, &total); > if (ret < 0) > - return -EINVAL; > + return ret; > > /* To protect from overflow, divide by 1024 */ > stat->busy_time = load >> 10; >
Thank you for the patch, LGTM. Some questions are still there, though. The function exynos5_performance_counters_init() should capture that the counters couldn't be enabled or set. So the functions: exynos5_counters_enable_edev() and exynos5_counters_set_event() must pass gently because devfreq device is registered. Then devfreq checks device status, and reaches the state when counters 'get' function returns that they are not ready...
If that is a kind of 2-stage initialization, maybe we should add another 'check' in the exynos5_performance_counters_init() and call the devfreq_event_get_event() to make sure that we are ready to go, otherwise return ret from that function (which is probably EPROBE_DEFER) and not register the devfreq device.
Marek do want to submit such patch or I should bake it and submit on top of this patch?
Could you tell me how I can reproduce this? Do you simply load one module after another (exynos-ppmu than exynos5422-dmc) or in parallel?
Regards, Lukasz
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