target/linux/bcm27xx/patches-4.19/950-0136-hwmon-raspberrypi-Prevent-voltage-low-warnings-from-.patch

   1 From e7056be388c7bbc6f0211f587643ff795ce30814 Mon Sep 17 00:00:00 2001
   2 From: Stefan Wahren <stefan.wahren@i2se.com>
   3 Date: Sat, 6 Oct 2018 16:46:18 +0200
   4 Subject: [PATCH] hwmon: raspberrypi: Prevent voltage low warnings from
   5  filling log
   6
   7 Although the correct fix for low voltage warnings is to
   8 improve the power supply, the current implementation
   9 of the detection can fill the log if the warning
  10 happens freqently. This replaces the logging with
  11 slightly custom ratelimited logging.
  12
  13 Signed-off-by: James Hughes <james.hughes@raspberrypi.org>
  14 Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
  15 ---
  16  drivers/hwmon/raspberrypi-hwmon.c | 41 ++++++++++++++++++++++++++++---
  17  1 file changed, 37 insertions(+), 4 deletions(-)
  18
  19 --- a/drivers/hwmon/raspberrypi-hwmon.c
  20 +++ b/drivers/hwmon/raspberrypi-hwmon.c
  21 @@ -15,6 +15,36 @@
  22  #include <linux/workqueue.h>
  23  #include <soc/bcm2835/raspberrypi-firmware.h>
  24
  25 +/*
  26 + * This section defines some rate limited logging that prevent
  27 + * repeated messages at much lower Hz than the default kernel settings.
  28 + * It's usually 5s, this is 5 minutes.
  29 + * Burst 3 means you may get three messages 'quickly', before
  30 + * the ratelimiting kicks in.
  31 + */
  32 +#define LOCAL_RATELIMIT_INTERVAL (5 * 60 * HZ)
  33 +#define LOCAL_RATELIMIT_BURST 3
  34 +
  35 +#ifdef CONFIG_PRINTK
  36 +#define printk_ratelimited_local(fmt, ...)     \
  37 +({                                             \
  38 +       static DEFINE_RATELIMIT_STATE(_rs,      \
  39 +               LOCAL_RATELIMIT_INTERVAL,       \
  40 +               LOCAL_RATELIMIT_BURST);         \
  41 +                                               \
  42 +       if (__ratelimit(&_rs))                  \
  43 +               printk(fmt, ##__VA_ARGS__);     \
  44 +})
  45 +#else
  46 +#define printk_ratelimited_local(fmt, ...)     \
  47 +       no_printk(fmt, ##__VA_ARGS__)
  48 +#endif
  49 +
  50 +#define pr_crit_ratelimited_local(fmt, ...)              \
  51 +       printk_ratelimited_local(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
  52 +#define pr_info_ratelimited_local(fmt, ...)              \
  53 +printk_ratelimited_local(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
  54 +
  55  #define UNDERVOLTAGE_STICKY_BIT        BIT(16)
  56
  57  struct rpi_hwmon_data {
  58 @@ -47,10 +77,13 @@ static void rpi_firmware_get_throttled(s
  59         if (new_uv == old_uv)
  60                 return;
  61
  62 -       if (new_uv)
  63 -               dev_crit(data->hwmon_dev, "Undervoltage detected!\n");
  64 -       else
  65 -               dev_info(data->hwmon_dev, "Voltage normalised\n");
  66 +       if (new_uv) {
  67 +               pr_crit_ratelimited_local("Under-voltage detected! (0x%08x)\n",
  68 +                                         value);
  69 +       } else {
  70 +               pr_info_ratelimited_local("Voltage normalised (0x%08x)\n",
  71 +                                         value);
  72 +       }
  73
  74         sysfs_notify(&data->hwmon_dev->kobj, NULL, "in0_lcrit_alarm");
  75  }