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