drivers/gpu/drm/i915/i915_utils.c

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright © 2019 Intel Corporation
   4  */
   5
   6 #include <drm/drm_drv.h>
   7
   8 #include "i915_drv.h"
   9 #include "i915_utils.h"
  10
  11 #define FDO_BUG_URL "https://bugs.freedesktop.org/enter_bug.cgi?product=DRI"
  12 #define FDO_BUG_MSG "Please file a bug at " FDO_BUG_URL " against DRM/Intel " \
  13                     "providing the dmesg log by booting with drm.debug=0xf"
  14
  15 void
  16 __i915_printk(struct drm_i915_private *dev_priv, const char *level,
  17               const char *fmt, ...)
  18 {
  19         static bool shown_bug_once;
  20         struct device *kdev = dev_priv->drm.dev;
  21         bool is_error = level[1] <= KERN_ERR[1];
  22         bool is_debug = level[1] == KERN_DEBUG[1];
  23         struct va_format vaf;
  24         va_list args;
  25
  26         if (is_debug && !drm_debug_enabled(DRM_UT_DRIVER))
  27                 return;
  28
  29         va_start(args, fmt);
  30
  31         vaf.fmt = fmt;
  32         vaf.va = &args;
  33
  34         if (is_error)
  35                 dev_printk(level, kdev, "%pV", &vaf);
  36         else
  37                 dev_printk(level, kdev, "[" DRM_NAME ":%ps] %pV",
  38                            __builtin_return_address(0), &vaf);
  39
  40         va_end(args);
  41
  42         if (is_error && !shown_bug_once) {
  43                 /*
  44                  * Ask the user to file a bug report for the error, except
  45                  * if they may have caused the bug by fiddling with unsafe
  46                  * module parameters.
  47                  */
  48                 if (!test_taint(TAINT_USER))
  49                         dev_notice(kdev, "%s", FDO_BUG_MSG);
  50                 shown_bug_once = true;
  51         }
  52 }
  53
  54 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
  55 static unsigned int i915_probe_fail_count;
  56
  57 int __i915_inject_probe_error(struct drm_i915_private *i915, int err,
  58                               const char *func, int line)
  59 {
  60         if (i915_probe_fail_count >= i915_modparams.inject_probe_failure)
  61                 return 0;
  62
  63         if (++i915_probe_fail_count < i915_modparams.inject_probe_failure)
  64                 return 0;
  65
  66         __i915_printk(i915, KERN_INFO,
  67                       "Injecting failure %d at checkpoint %u [%s:%d]\n",
  68                       err, i915_modparams.inject_probe_failure, func, line);
  69         i915_modparams.inject_probe_failure = 0;
  70         return err;
  71 }
  72
  73 bool i915_error_injected(void)
  74 {
  75         return i915_probe_fail_count && !i915_modparams.inject_probe_failure;
  76 }
  77
  78 #endif
  79
  80 void cancel_timer(struct timer_list *t)
  81 {
  82         if (!READ_ONCE(t->expires))
  83                 return;
  84
  85         del_timer(t);
  86         WRITE_ONCE(t->expires, 0);
  87 }
  88
  89 void set_timer_ms(struct timer_list *t, unsigned long timeout)
  90 {
  91         if (!timeout) {
  92                 cancel_timer(t);
  93                 return;
  94         }
  95
  96         timeout = msecs_to_jiffies_timeout(timeout);
  97
  98         /*
  99          * Paranoia to make sure the compiler computes the timeout before
 100          * loading 'jiffies' as jiffies is volatile and may be updated in
 101          * the background by a timer tick. All to reduce the complexity
 102          * of the addition and reduce the risk of losing a jiffie.
 103          */
 104         barrier();
 105
 106         mod_timer(t, jiffies + timeout);
 107 }