target/linux/brcm2708/patches-4.14/950-0278-Prevent-voltage-low-warnings-from-filling-log.patch

   1 From cecce8a9e798fbe8571381b6f9f69fd7a0defa37 Mon Sep 17 00:00:00 2001
   2 From: James Hughes <james.hughes@raspberrypi.org>
   3 Date: Wed, 18 Apr 2018 13:02:57 +0100
   4 Subject: [PATCH 278/454] Prevent voltage low warnings from filling log
   5
   6 Although the correct fix for low voltage warnings is to
   7 improve the power supply, the current implementation
   8 of the detection can fill the log if the warning
   9 happens freqently. This replaces the logging with
  10 slightly custom ratelimited logging.
  11
  12 Signed-off-by: James Hughes <james.hughes@raspberrypi.org>
  13 ---
  14  drivers/firmware/raspberrypi.c | 40 ++++++++++++++++++++++++++++++++--
  15  1 file changed, 38 insertions(+), 2 deletions(-)
  16
  17 --- a/drivers/firmware/raspberrypi.c
  18 +++ b/drivers/firmware/raspberrypi.c
  19 @@ -24,6 +24,38 @@
  20
  21  #define UNDERVOLTAGE_BIT               BIT(0)
  22
  23 +
  24 +/*
  25 + * This section defines some rate limited logging that prevent
  26 + * repeated messages at much lower Hz than the default kernel settings.
  27 + * It's usually 5s, this is 5 minutes.
  28 + * Burst 3 means you may get three messages 'quickly', before
  29 + * the ratelimiting kicks in.
  30 + */
  31 +#define LOCAL_RATELIMIT_INTERVAL (5 * 60 * HZ)
  32 +#define LOCAL_RATELIMIT_BURST 3
  33 +
  34 +#ifdef CONFIG_PRINTK
  35 +#define printk_ratelimited_local(fmt, ...)     \
  36 +({                                             \
  37 +       static DEFINE_RATELIMIT_STATE(_rs,      \
  38 +               LOCAL_RATELIMIT_INTERVAL,       \
  39 +               LOCAL_RATELIMIT_BURST);         \
  40 +                                               \
  41 +       if (__ratelimit(&_rs))                  \
  42 +               printk(fmt, ##__VA_ARGS__);     \
  43 +})
  44 +#else
  45 +#define printk_ratelimited_local(fmt, ...)     \
  46 +       no_printk(fmt, ##__VA_ARGS__)
  47 +#endif
  48 +
  49 +#define pr_crit_ratelimited_local(fmt, ...)              \
  50 +       printk_ratelimited_local(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
  51 +#define pr_info_ratelimited_local(fmt, ...)              \
  52 +       printk_ratelimited_local(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
  53 +
  54 +
  55  struct rpi_firmware {
  56         struct mbox_client cl;
  57         struct mbox_chan *chan; /* The property channel. */
  58 @@ -216,9 +248,13 @@ static int rpi_firmware_get_throttled(st
  59
  60         if (new_uv != old_uv) {
  61                 if (new_uv)
  62 -                       pr_crit("Under-voltage detected! (0x%08x)\n", *value);
  63 +                       pr_crit_ratelimited_local(
  64 +                               "Under-voltage detected! (0x%08x)\n",
  65 +                                *value);
  66                 else
  67 -                       pr_info("Voltage normalised (0x%08x)\n", *value);
  68 +                       pr_info_ratelimited_local(
  69 +                               "Voltage normalised (0x%08x)\n",
  70 +                                *value);
  71         }
  72
  73         sysfs_notify(&fw->cl.dev->kobj, NULL, "get_throttled");