target/linux/s3c24xx/patches-2.6.24/1284-fix-one-mmc-race.patch.patch

   1 From d744c88c149269b95ec068c8615e492375415d6d Mon Sep 17 00:00:00 2001
   2 From: Andy Green <andy@openmoko.com>
   3 Date: Wed, 27 Aug 2008 04:09:30 +0900
   4 Subject: [PATCH] fix-one-mmc-race.patch
   5
   6 Some boots from Qi trigger a symptom from this interesting race -->
   7
   8 [    2.730000] Unable to handle kernel NULL pointer dereference at virtual address 00000248
   9 [    2.730000] pgd = c0004000
  10 [    2.735000] [00000248] *pgd=00000000
  11 [    2.735000] Internal error: Oops: 5 [#1] PREEMPT
  12 [    2.735000] Modules linked in:
  13 [    2.735000] CPU: 0    Not tainted  (2.6.24-stable10_0c1587137aaf0ee3-mokodev #1071)
  14 [    2.735000] PC is at pcf50633_voltage_set+0x1c/0xfc
  15 [    2.735000] LR is at gta02_glamo_mmc_set_power+0xdc/0x128
  16 [    2.735000] pc : [<c01df570>]    lr : [<c0034324>]    psr: 60000013
  17 [    2.735000] sp : c7c57eb0  ip : c7c57ec8  fp : c7c57ec4
  18 [    2.735000] r10: c7cfca28  r9 : 00000000  r8 : c7c57f68
  19 [    2.735000] r7 : c7cfca68  r6 : c7cfcae0  r5 : 00000c80  r4 : 00000000
  20 [    2.735000] r3 : 00000000  r2 : 00000c80  r1 : 0000000a  r0 : 00000c80
  21 [    2.735000] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
  22 [    2.735000] Control: c000717f  Table: 30004000  DAC: 00000017
  23 [    2.735000] Process kmmcd (pid: 102, stack limit = 0xc7c56268)
  24 [    2.735000] Stack: (0xc7c57eb0 to 0xc7c58000)
  25 [    2.735000] 7ea0:                                     c0608c58 00000c80 c7c57edc c7c57ec8
  26 [    2.735000] 7ec0: c0034324 c01df564 c7cfca28 c7cfc800 c7c57f1c c7c57ee0 c0194de0 c0034258
  27 [    2.735000] 7ee0: c7c57f34 c7c57ef0 c01e6230 c005de5c 60000013 c7cfca28 c7cfc800 60000013
  28 [    2.735000] 7f00: c7cfca68 c7c57f68 00000000 c01e6778 c7c57f34 c7c57f20 c01e5d68 c0194da8
  29 [    2.735000] 7f20: c7cfc800 c7cfca08 c7c57f5c c7c57f38 c01e6810 c01e5cbc c0059278 c7c57f48
  30 [    2.735000] 7f40: c02d2ba0 00000002 c7c44420 c7c56000 c7c57f9c c7c57f60 c00592e0 c01e6788
  31 [    2.735000] 7f60: 00000002 c0059278 c0608d74 c04321cc c036e16c 00000000 c7c57fb0 c7c44420
  32 [    2.735000] 7f80: c7c56000 00000000 00000000 00000000 c7c57fd4 c7c57fa0 c005a068 c00591ec
  33 [    2.735000] 7fa0: c02d0624 00000000 c7c4c0e0 c005dc2c c7c57fb0 c7c57fb0 00000000 c7c56000
  34 [    2.735000] 7fc0: c7c44420 c0059f84 c7c57ff4 c7c57fd8 c005db28 c0059f94 00000000 00000000
  35 [    2.735000] 7fe0: 00000000 00000000 00000000 c7c57ff8 c004b170 c005dad8 ffffffff ffffffff
  36 [    2.735000] Backtrace:
  37 [    2.735000] [<c01df554>] (pcf50633_voltage_set+0x0/0xfc) from [<c0034324>] (gta02_glamo_mmc_set_power+0xdc/0x128)
  38 [    2.735000]  r5:00000c80 r4:c0608c58
  39 [    2.735000] [<c0034248>] (gta02_glamo_mmc_set_power+0x0/0x128) from [<c0194de0>] (glamo_mci_set_ios+0x48/0x254)
  40 [    2.735000]  r5:c7cfc800 r4:c7cfca28
  41 [    2.735000] [<c0194d98>] (glamo_mci_set_ios+0x0/0x254) from [<c01e5d68>] (mmc_power_up+0xbc/0x100)
  42 [    2.735000] [<c01e5cac>] (mmc_power_up+0x0/0x100) from [<c01e6810>] (mmc_rescan+0x98/0x1a8)
  43 [    2.735000]  r5:c7cfca08 r4:c7cfc800
  44 [    2.735000] [<c01e6778>] (mmc_rescan+0x0/0x1a8) from [<c00592e0>] (run_workqueue+0x104/0x208)
  45 [    2.735000]  r6:c7c56000 r5:c7c44420 r4:00000002
  46 [    2.735000] [<c00591dc>] (run_workqueue+0x0/0x208) from [<c005a068>] (worker_thread+0xe4/0xf8)
  47 [    2.735000] [<c0059f84>] (worker_thread+0x0/0xf8) from [<c005db28>] (kthread+0x60/0x94)
  48 [    2.735000]  r6:c0059f84 r5:c7c44420 r4:c7c56000
  49 [    2.735000] [<c005dac8>] (kthread+0x0/0x94) from [<c004b170>] (do_exit+0x0/0x6f4)
  50 [    2.735000]  r6:00000000 r5:00000000 r4:00000000
  51 [    2.735000] Code: e351000a e1a04000 e1a00002 8a000032 (e5943248)
  52 [    2.745000] ---[ end trace 123ec1d286354824 ]---
  53
  54 This problem was caused by insufficient timeout waiting for pcf50633 to resume
  55 and broken code to detect timeout exhaustion.
  56
  57 Although I'd like to think it has something to do with mmc resume woes it should make a panic
  58 and subsequent emergency spew on UART2 if that had been the case.
  59
  60 Took the opportunity to move the stuff to show completion of probe to later in the
  61 pcf50633 probe and tighten readiness test.
  62
  63 Signed-off-by: Andy Green <andy@openmoko.com>
  64 ---
  65  arch/arm/mach-s3c2440/mach-gta02.c |    4 ++--
  66  drivers/i2c/chips/pcf50633.c       |   12 ++++++++----
  67  2 files changed, 10 insertions(+), 6 deletions(-)
  68
  69 diff --git a/arch/arm/mach-s3c2440/mach-gta02.c b/arch/arm/mach-s3c2440/mach-gta02.c
  70 index eadf88a..c15f072 100644
  71 --- a/arch/arm/mach-s3c2440/mach-gta02.c
  72 +++ b/arch/arm/mach-s3c2440/mach-gta02.c
  73 @@ -1357,7 +1357,7 @@ static void
  74  gta02_glamo_mmc_set_power(unsigned char power_mode, unsigned short vdd)
  75  {
  76         int mv = 1650;
  77 -       int timeout = 100;
  78 +       int timeout = 500;
  79
  80         printk(KERN_DEBUG "mmc_set_power(power_mode=%u, vdd=%u\n",
  81                power_mode, vdd);
  82 @@ -1377,7 +1377,7 @@ gta02_glamo_mmc_set_power(unsigned char power_mode, unsigned short vdd)
  83                         while (pcf50633_ready(pcf50633_global) && (timeout--))
  84                                 msleep(5);
  85
  86 -                       if (!timeout) {
  87 +                       if (timeout < 0) {
  88                                 printk(KERN_ERR"gta02_glamo_mmc_set_power "
  89                                              "BAILING on timeout\n");
  90                                 return;
  91 diff --git a/drivers/i2c/chips/pcf50633.c b/drivers/i2c/chips/pcf50633.c
  92 index b90ea8c..bac307e 100644
  93 --- a/drivers/i2c/chips/pcf50633.c
  94 +++ b/drivers/i2c/chips/pcf50633.c
  95 @@ -2151,8 +2151,6 @@ static int pcf50633_detect(struct i2c_adapter *adapter, int address, int kind)
  96                 goto exit_free;
  97         }
  98
  99 -       pcf50633_global = pcf;
 100 -
 101         init_resume_dependency_list(&pcf->resume_dependency);
 102
 103         populate_sysfs_group(pcf);
 104 @@ -2228,11 +2226,13 @@ static int pcf50633_detect(struct i2c_adapter *adapter, int address, int kind)
 105                 backlight_update_status(pcf->backlight);
 106         }
 107
 108 -       pcf->probe_completed = 1;
 109 -
 110         if (pcf->pdata->flag_use_apm_emulation)
 111                 apm_get_power_status = pcf50633_get_power_status;
 112
 113 +       pcf->probe_completed = 1;
 114 +       pcf50633_global = pcf;
 115 +       dev_info(&new_client->dev, "probe completed\n");
 116 +
 117         /* if platform was interested, give him a chance to register
 118          * platform devices that switch power with us as the parent
 119          * at registration time -- ensures suspend / resume ordering
 120 @@ -2476,6 +2476,10 @@ int pcf50633_ready(struct pcf50633_data *pcf)
 121         if (!pcf)
 122                 return -EACCES;
 123
 124 +       /* this was seen during boot with Qi, mmc_rescan racing us */
 125 +       if (!pcf->probe_completed)
 126 +               return -EACCES;
 127 +
 128         if ((pcf->suspend_state != PCF50633_SS_RUNNING) &&
 129             (pcf->suspend_state < PCF50633_SS_COMPLETED_RESUME))
 130                 return -EBUSY;
 131 --
 132 1.5.6.5
 133