target/linux/s3c24xx/patches-2.6.24/1271-always-call-resume-dependencies.patch.patch

   1 From 36879992de8774cbf8686740bbda383cc6fbdcbb Mon Sep 17 00:00:00 2001
   2 From: \\\\\\\"Mike (mwester)\\\\\\ <mwester@dls.net>
   3 Date: Mon, 11 Aug 2008 20:16:09 +0100
   4 Subject: [PATCH] always-call-resume-dependencies.patch
   5
   6 Attached is a patch that has greatly reduced the frequency of failures
   7 to resume (due to an oops from the glamo resume handler), and the
   8 dreaded "white screen after resume".  I can't say that it fixes all of
   9 these, although I have yet to see the white-screen since applying this
  10 patch and suspending/resuming several hundred times (with the 30-second
  11 suspend on the 2008.8 image and the endless stream of GSM error messages
  12 generated by something in that image, it has proved to be very useful to
  13 do an automated stress test!)
  14
  15 This patch will apply to stable, and should make stable slightly more,
  16 well, "stable".
  17
  18 [Feel free to remove the debug messages if someone feels strongly about
  19 that; I left them in because I think they might be useful in triaging
  20 further crashes; I'm not at all convinced that this patch will fix all
  21 the cases of resume failures.]
  22
  23 [[And, yes, this is ugly, really ugly.]]
  24
  25 [[[Oh yeah - there's still one extreme case that will result in an oops:
  26  if a dependent driver is built as a module, and it is unloaded, and it
  27 happened that the preceding suspend/resume was aborted, and that abort
  28 happened between the dependent driver and the driver upon which it is
  29 dependent, then a list entry will be left behind referencing the
  30 unloaded module.  There's just no good way to fix that given the way the
  31 resume dependency plumbing is connected up right now, so just avoid
  32 using modules for any of the drivers involved in the resume dependency
  33 stuff.]]]
  34
  35 Regards,
  36 Mike (mwester)
  37 commit 905d2fc9c45f622418ce9ef4e67c23453aab7571
  38 Author: Mike Westerhof <mwester@dls.net>
  39 Date:   Mon Aug 11 11:11:25 2008 -0500
  40
  41     always-call-resume-dependencies.patch
  42
  43     Ensure that a dependent resume handler is always executed,
  44     even if the resume handler for driver upon which it is
  45     dependent never suspends (and therefore never resumes either).
  46     Also make sure that we do not end up with duplicate
  47     dependencies registered, something that can happen if the
  48     suspend is aborted due to driver failure or an early resume
  49     (such as occurs when the GSM interrupts during suspend).
  50
  51     Signed-off-by: Mike Westerhof <mwester@dls.net>
  52 ---
  53  drivers/i2c/chips/pcf50633.c      |    6 +++++
  54  drivers/mfd/glamo/glamo-core.c    |    5 ++++
  55  drivers/mfd/glamo/glamo-core.h    |    1 +
  56  drivers/serial/s3c2410.c          |    7 ++++++
  57  include/linux/resume-dependency.h |   38 ++++++++++++++++++++++++++++++++++++-
  58  5 files changed, 56 insertions(+), 1 deletions(-)
  59
  60 diff --git a/drivers/i2c/chips/pcf50633.c b/drivers/i2c/chips/pcf50633.c
  61 index 98c254c..b90ea8c 100644
  62 --- a/drivers/i2c/chips/pcf50633.c
  63 +++ b/drivers/i2c/chips/pcf50633.c
  64 @@ -183,6 +183,7 @@ struct pcf50633_data {
  65         } standby_regs;
  66
  67         struct resume_dependency resume_dependency;
  68 +       int is_suspended;
  69
  70  #endif
  71  };
  72 @@ -2366,6 +2367,8 @@ void pcf50633_register_resume_dependency(struct pcf50633_data *pcf,
  73                                         struct resume_dependency *dep)
  74  {
  75         register_resume_dependency(&pcf->resume_dependency, dep);
  76 +       if (pcf->is_suspended)
  77 +               activate_all_resume_dependencies(&pcf->resume_dependency);
  78  }
  79  EXPORT_SYMBOL_GPL(pcf50633_register_resume_dependency);
  80
  81 @@ -2462,6 +2465,8 @@ static int pcf50633_suspend(struct device *dev, pm_message_t state)
  82
  83         mutex_unlock(&pcf->lock);
  84
  85 +       pcf->is_suspended = 1;
  86 +       activate_all_resume_dependencies(&pcf->resume_dependency);
  87         return 0;
  88  }
  89
  90 @@ -2590,6 +2595,7 @@ static int pcf50633_resume(struct device *dev)
  91         get_device(&pcf->client.dev);
  92         pcf50633_work(&pcf->work);
  93
  94 +       pcf->is_suspended = 0;
  95         callback_all_resume_dependencies(&pcf->resume_dependency);
  96
  97         return 0;
  98 diff --git a/drivers/mfd/glamo/glamo-core.c b/drivers/mfd/glamo/glamo-core.c
  99 index c094a8c..e310382 100644
 100 --- a/drivers/mfd/glamo/glamo-core.c
 101 +++ b/drivers/mfd/glamo/glamo-core.c
 102 @@ -1248,6 +1248,8 @@ void glamo_register_resume_dependency(struct resume_dependency *
 103  {
 104         register_resume_dependency(&glamo_handle->resume_dependency,
 105                                                              resume_dependency);
 106 +       if (glamo_handle->is_suspended)
 107 +               activate_all_resume_dependencies(&glamo_handle->resume_dependency);
 108  }
 109  EXPORT_SYMBOL_GPL(glamo_register_resume_dependency);
 110
 111 @@ -1255,12 +1257,15 @@ EXPORT_SYMBOL_GPL(glamo_register_resume_dependency);
 112  static int glamo_suspend(struct platform_device *pdev, pm_message_t state)
 113  {
 114         glamo_power(glamo_handle, GLAMO_POWER_SUSPEND);
 115 +       glamo_handle->is_suspended = 1;
 116 +       activate_all_resume_dependencies(&glamo_handle->resume_dependency);
 117         return 0;
 118  }
 119
 120  static int glamo_resume(struct platform_device *pdev)
 121  {
 122         glamo_power(glamo_handle, GLAMO_POWER_ON);
 123 +       glamo_handle->is_suspended = 0;
 124         callback_all_resume_dependencies(&glamo_handle->resume_dependency);
 125
 126         return 0;
 127 diff --git a/drivers/mfd/glamo/glamo-core.h b/drivers/mfd/glamo/glamo-core.h
 128 index d3f4309..ac5eacf 100644
 129 --- a/drivers/mfd/glamo/glamo-core.h
 130 +++ b/drivers/mfd/glamo/glamo-core.h
 131 @@ -32,6 +32,7 @@ struct glamo_core {
 132         struct resume_dependency resume_dependency;
 133         u32 engine_enabled_bitfield;
 134         u32 engine_enabled_bitfield_suspend;
 135 +       int is_suspended;
 136  };
 137
 138  struct glamo_script {
 139 diff --git a/drivers/serial/s3c2410.c b/drivers/serial/s3c2410.c
 140 index 2a388cf..3b1c07b 100644
 141 --- a/drivers/serial/s3c2410.c
 142 +++ b/drivers/serial/s3c2410.c
 143 @@ -116,6 +116,7 @@ struct s3c24xx_uart_port {
 144         struct uart_port                port;
 145
 146         struct resume_dependency        resume_dependency;
 147 +       int                             is_suspended;
 148  };
 149
 150
 151 @@ -1188,10 +1189,13 @@ static int s3c24xx_serial_remove(struct platform_device *dev)
 152  static int s3c24xx_serial_suspend(struct platform_device *dev, pm_message_t state)
 153  {
 154         struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);
 155 +       struct s3c24xx_uart_port *ourport = to_ourport(port);
 156
 157         if (port)
 158                 uart_suspend_port(&s3c24xx_uart_drv, port);
 159
 160 +       activate_all_resume_dependencies(&ourport->resume_dependency);
 161 +       ourport->is_suspended = 1;
 162         return 0;
 163  }
 164
 165 @@ -1202,6 +1206,8 @@ void s3c24xx_serial_register_resume_dependency(struct resume_dependency *
 166
 167         register_resume_dependency(&ourport->resume_dependency,
 168                                                              resume_dependency);
 169 +       if (ourport->is_suspended)
 170 +               activate_all_resume_dependencies(&ourport->resume_dependency);
 171  }
 172  EXPORT_SYMBOL(s3c24xx_serial_register_resume_dependency);
 173
 174 @@ -1218,6 +1224,7 @@ static int s3c24xx_serial_resume(struct platform_device *dev)
 175                 uart_resume_port(&s3c24xx_uart_drv, port);
 176         }
 177
 178 +       ourport->is_suspended = 0;
 179         callback_all_resume_dependencies(&ourport->resume_dependency);
 180
 181         return 0;
 182 diff --git a/include/linux/resume-dependency.h b/include/linux/resume-dependency.h
 183 index e0c0f33..959cadd 100644
 184 --- a/include/linux/resume-dependency.h
 185 +++ b/include/linux/resume-dependency.h
 186 @@ -38,6 +38,7 @@ struct resume_dependency {
 187   */
 188
 189  #define init_resume_dependency_list(_head) \
 190 +       printk(KERN_ERR "##### init_resume_dependency_list(head=%p)\n", (_head)); \
 191         INIT_LIST_HEAD(&(_head)->list);
 192
 193
 194 @@ -48,7 +49,18 @@ struct resume_dependency {
 195   */
 196
 197  #define register_resume_dependency(_head, _dep) { \
 198 -       (_dep)->called_flag = 0; \
 199 +       struct list_head *_pos, *_q; \
 200 +       struct resume_dependency *_d; \
 201 +\
 202 +       printk(KERN_ERR "##### register_resume_dependency(head=%p, dep=%p)\n", (_head), (_dep)); \
 203 +       (_dep)->called_flag = 1; \
 204 +       list_for_each_safe(_pos, _q, &((_head)->list)) { \
 205 +               _d = list_entry(_pos, struct resume_dependency, list); \
 206 +               if (_d == (_dep)) { \
 207 +                       list_del(_pos); \
 208 +                       printk(KERN_ERR "#####   duplicate dependency removed first\n"); \
 209 +               } \
 210 +       } \
 211         list_add(&(_dep)->list, &(_head)->list); \
 212  }
 213
 214 @@ -61,14 +73,38 @@ struct resume_dependency {
 215         struct list_head *_pos, *_q; \
 216         struct resume_dependency *_dep; \
 217  \
 218 +       printk(KERN_ERR "##### callback_all_resume_dependencies(head=%p)\n", (_head)); \
 219         list_for_each_safe(_pos, _q, &((_head)->list)) { \
 220                 _dep = list_entry(_pos, struct resume_dependency, list); \
 221 +               printk(KERN_ERR "#####   callback list entry (head=%p, dep=%p)\n", (_head), (_dep)); \
 222                 _dep->called_flag = 1; \
 223 +               printk(KERN_ERR "#####      callback=%p(context=%p))\n", (_dep->callback),(_dep->context)); \
 224                 (_dep->callback)(_dep->context); \
 225                 list_del(_pos); \
 226         } \
 227  }
 228
 229 +/* When a dependency is added, it is not actually active; the dependent resume
 230 + * handler will function as normal.  The dependency is activated by the suspend
 231 + * handler for the driver that will be doing the callbacks.  This ensures that
 232 + * if the suspend is aborted for any reason (error, driver busy, etc), that all
 233 + * suspended drivers will resume, even if the driver upon which they are dependent
 234 + * did not suspend, and hence will not resume, and thus would be unable to perform
 235 + * the callbacks.
 236 + */
 237 +
 238 +#define activate_all_resume_dependencies(_head) { \
 239 +       struct list_head *_pos, *_q; \
 240 +       struct resume_dependency *_dep; \
 241 +\
 242 +       printk(KERN_ERR "##### activate_all_resume_dependencies(head=%p)\n", (_head)); \
 243 +       list_for_each_safe(_pos, _q, &((_head)->list)) { \
 244 +               _dep = list_entry(_pos, struct resume_dependency, list); \
 245 +               printk(KERN_ERR "#####   activating callback list entry (head=%p, dep=%p)\n", (_head), (_dep)); \
 246 +               _dep->called_flag = 0; \
 247 +       } \
 248 +}
 249 +
 250  /* if your resume action is dependent on multiple drivers being resumed already,
 251   * register the same callback with each driver you are dependent on, and check
 252   * .called_flag for all of the struct resume_dependency.  When they are all 1
 253 --
 254 1.5.6.5
 255