Re: [PATCH] [ARM] omap: resource: Make resource_refresh() thread safe.

2009-09-11 Thread Kevin Hilman 
Mike Turquette mturque...@ti.com writes:

 Kevin Hilman wrote:
 Mike Chan m...@android.com writes:

 Need to lock the res_mutex when traversing the res_list.

 Signed-off-by: Mike Chan m...@android.com

 Looks good, thanks.

 This patch causes a hang for me when transitioning to OFF mode.  This
 was tested on the Android 2.6.29 tree and is 100% reproducible.  The
 moment a user runs 'echo 1  /sys/power/enable_off_mode' the board
 hangs without any further output.

 Reverting the patch allows me to hit OFF mode again.  I haven't yet
 tested this on vanilla 2.6.29 or latest L-O.


OK, reverting this in both PM branches.  Looks like a deadlock to me,
as update_resource_level() must cause a call to something else that
takes the mutex.

Kevin


 Pushed to PM branch and pm-2.6.29.

 Kevin

 ---
  arch/arm/plat-omap/resource.c |2 ++
  1 files changed, 2 insertions(+), 0 deletions(-)

 diff --git a/arch/arm/plat-omap/resource.c b/arch/arm/plat-omap/resource.c
 index 25072cd..4631912 100644
 --- a/arch/arm/plat-omap/resource.c
 +++ b/arch/arm/plat-omap/resource.c
 @@ -234,11 +234,13 @@ int resource_refresh(void)
 struct shared_resource *resp = NULL;
 int ret = 0;
  +  down(res_mutex);
 list_for_each_entry(resp, res_list, node) {
 ret = update_resource_level(resp);
 if (ret)
 break;
 }
 +   up(res_mutex);
 return ret;
  }
  -- 
 1.5.4.5
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Re: [PATCH] [ARM] omap: resource: Make resource_refresh() thread safe.

2009-09-11 Thread Mike Chan 
On Fri, Sep 11, 2009 at 2:10 PM, Kevin
Hilmankhil...@deeprootsystems.com wrote:
 Mike Turquette mturque...@ti.com writes:

 Kevin Hilman wrote:
 Mike Chan m...@android.com writes:

 Need to lock the res_mutex when traversing the res_list.

 Signed-off-by: Mike Chan m...@android.com

 Looks good, thanks.

 This patch causes a hang for me when transitioning to OFF mode.  This
 was tested on the Android 2.6.29 tree and is 100% reproducible.  The
 moment a user runs 'echo 1  /sys/power/enable_off_mode' the board
 hangs without any further output.

 Reverting the patch allows me to hit OFF mode again.  I haven't yet
 tested this on vanilla 2.6.29 or latest L-O.


 OK, reverting this in both PM branches.  Looks like a deadlock to me,
 as update_resource_level() must cause a call to something else that
 takes the mutex.


Good catch, I see the deadlock are in the change_level function
pointers. Where set_xxx will call resource_request() or
resource_release() = resource_lookup() which grabs the list mutex we
grabbed in resource_refresh().

Thoughts on changing the mutex to a RW semaphore?

-- Mike

 Kevin


 Pushed to PM branch and pm-2.6.29.

 Kevin

 ---
  arch/arm/plat-omap/resource.c |    2 ++
  1 files changed, 2 insertions(+), 0 deletions(-)

 diff --git a/arch/arm/plat-omap/resource.c b/arch/arm/plat-omap/resource.c
 index 25072cd..4631912 100644
 --- a/arch/arm/plat-omap/resource.c
 +++ b/arch/arm/plat-omap/resource.c
 @@ -234,11 +234,13 @@ int resource_refresh(void)
     struct shared_resource *resp = NULL;
     int ret = 0;
  +  down(res_mutex);
     list_for_each_entry(resp, res_list, node) {
             ret = update_resource_level(resp);
             if (ret)
                     break;
     }
 +   up(res_mutex);
     return ret;
  }
  --
 1.5.4.5
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Re: [PATCH] [ARM] omap: resource: Make resource_refresh() thread safe.

2009-09-10 Thread Mike Turquette 

Kevin Hilman wrote:

Mike Chan m...@android.com writes:


Need to lock the res_mutex when traversing the res_list.

Signed-off-by: Mike Chan m...@android.com


Looks good, thanks.


This patch causes a hang for me when transitioning to OFF mode.  This 
was tested on the Android 2.6.29 tree and is 100% reproducible.  The 
moment a user runs 'echo 1  /sys/power/enable_off_mode' the board hangs 
without any further output.


Reverting the patch allows me to hit OFF mode again.  I haven't yet 
tested this on vanilla 2.6.29 or latest L-O.


Mike


Pushed to PM branch and pm-2.6.29.

Kevin


---
 arch/arm/plat-omap/resource.c |2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/arm/plat-omap/resource.c b/arch/arm/plat-omap/resource.c
index 25072cd..4631912 100644
--- a/arch/arm/plat-omap/resource.c
+++ b/arch/arm/plat-omap/resource.c
@@ -234,11 +234,13 @@ int resource_refresh(void)
struct shared_resource *resp = NULL;
int ret = 0;
 
+	down(res_mutex);

list_for_each_entry(resp, res_list, node) {
ret = update_resource_level(resp);
if (ret)
break;
}
+   up(res_mutex);
return ret;
 }
 
--

1.5.4.5

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Re: [PATCH] [ARM] omap: resource: Make resource_refresh() thread safe.

2009-09-08 Thread Kevin Hilman 
Mike Chan m...@android.com writes:

 Need to lock the res_mutex when traversing the res_list.

 Signed-off-by: Mike Chan m...@android.com

Looks good, thanks.

Pushed to PM branch and pm-2.6.29.

Kevin

 ---
  arch/arm/plat-omap/resource.c |2 ++
  1 files changed, 2 insertions(+), 0 deletions(-)

 diff --git a/arch/arm/plat-omap/resource.c b/arch/arm/plat-omap/resource.c
 index 25072cd..4631912 100644
 --- a/arch/arm/plat-omap/resource.c
 +++ b/arch/arm/plat-omap/resource.c
 @@ -234,11 +234,13 @@ int resource_refresh(void)
   struct shared_resource *resp = NULL;
   int ret = 0;
  
 + down(res_mutex);
   list_for_each_entry(resp, res_list, node) {
   ret = update_resource_level(resp);
   if (ret)
   break;
   }
 + up(res_mutex);
   return ret;
  }
  
 -- 
 1.5.4.5
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[PATCH] [ARM] omap: resource: Make resource_refresh() thread safe.

2009-09-03 Thread Mike Chan 
Need to lock the res_mutex when traversing the res_list.

Signed-off-by: Mike Chan m...@android.com
---
 arch/arm/plat-omap/resource.c |2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/arm/plat-omap/resource.c b/arch/arm/plat-omap/resource.c
index 25072cd..4631912 100644
--- a/arch/arm/plat-omap/resource.c
+++ b/arch/arm/plat-omap/resource.c
@@ -234,11 +234,13 @@ int resource_refresh(void)
struct shared_resource *resp = NULL;
int ret = 0;
 
+   down(res_mutex);
list_for_each_entry(resp, res_list, node) {
ret = update_resource_level(resp);
if (ret)
break;
}
+   up(res_mutex);
return ret;
 }
 
-- 
1.5.4.5

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