[PATCH] snowball: android: mali: Disable profiling of Mali L2 cache

[Jon Medhurst (Tixy)]

Ping, this patch doesn't seem to have made it into the Snowball Android
kernel, or have I missed it?

On Sat, 2012-03-24 at 12:47 +0000, Jon Medhurst (Tixy) wrote:
> When connecting the ARM Streamline Performance Analyzer to Snowball
> Android this will cause a board lock-up if the screen is static
> (Bug #961962). The cause of this appears to be a know issue with reading
> the L2 cache performance counters whilst the hardware block is powered
> down.
> 
> As the current code is written to access these counters even when they
> have not been explicitly selected then this issue prevents Streamline
> being used reliably for any purpose.
> 
> To workaround this bug, this patch disables support for the L2 cache
> counters in Mali. This has no effect on the operation of the cache.
> 
> Signed-off-by: Jon Medhurst <tixy at linaro.org>
> ---
>  .../mali/linux/mali_osk_profiling_gator.c          |    8 +++++---
>  1 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/mali/mali400ko/driver/src/devicedrv/mali/linux/mali_osk_profiling_gator.c b/drivers/gpu/mali/mali400ko/driver/src/devicedrv/mali/linux/mali_osk_profiling_gator.c
> index c4cd582..7ebc673 100644
> --- a/drivers/gpu/mali/mali400ko/driver/src/devicedrv/mali/linux/mali_osk_profiling_gator.c
> +++ b/drivers/gpu/mali/mali400ko/driver/src/devicedrv/mali/linux/mali_osk_profiling_gator.c
> @@ -11,6 +11,8 @@
>   * Boston, MA  02110-1301, USA.
>   */
>  
> +#define DONT_USE_L2_CACHE_COUNTERS /* These traces can cause lock-ups so disable them. */
> +
>  #include <linux/module.h>
>  
>  #include "mali_kernel_common.h"
> @@ -19,7 +21,7 @@
>  #include "mali_osk_profiling.h"
>  #include "mali_linux_trace.h"
>  
> -#if defined(USING_MALI400_L2_CACHE)
> +#if defined(USING_MALI400_L2_CACHE) && !defined(DONT_USE_L2_CACHE_COUNTERS)
>  #include "mali_kernel_l2_cache.h"
>  #endif /* USING_MALI400_L2_CACHE */
>  
> @@ -180,7 +182,7 @@ _mali_osk_errcode_t _mali_ukk_profiling_get_config(_mali_uk_profiling_get_config
>   */
>  int _mali_profiling_set_event(u32 counter_id, s32 event_id)
>  {
> -#if defined(USING_MALI400_L2_CACHE)
> +#if defined(USING_MALI400_L2_CACHE) && !defined(DONT_USE_L2_CACHE_COUNTERS)
>      /* 
>       * The L2 cache counters have special handling in the driver. Since we
>       * receive new event IDs for each counter one at a time, we need to know
> @@ -224,7 +226,7 @@ int _mali_profiling_set_event(u32 counter_id, s32 event_id)
>      return 0;
>  }
>  
> -#if defined(USING_MALI400_L2_CACHE)
> +#if defined(USING_MALI400_L2_CACHE) && !defined(DONT_USE_L2_CACHE_COUNTERS)
>  /**
>   * Called by gator.ko to retrieve the L2 cache counter values. The L2 cache
>   * counters are unique in that they are polled by gator, rather than being