Re: [PATCH] PM-WIP-OPP: Fixing wrong target level being passed during Core DVFS.

["Menon, Nishanth" <nm@ti.com>]

Gopinath, Thara said the following on 02/18/2010 10:31 AM:
> As per the current implementaion (u8*)&target_level is being passed
> to freq_to_opp in set_opp. This would result in updating just the first
> 8 bits of a u32 variable. Later target_level is passed to
> resource_set_opp_level as a u32 parameter. This maens
> a. Initially target_level was 0xabcdefgh.
> b. freq_to_opp updates the lower eight bits of target_level
> to 0xXX. Now target_level = 0xabcdefXX.
> c. We pass 0xabcdefXX as target_level to resource_set_opp_level
> when we want to pass just 0xXX.
> This is leading to some corrupted bookkeeping later on in the
> dvfs path.
> 
> This patch ensures that target_level passed to resource_set_opp_level
> is actually the level that is intended by freq_to_opp API.

Thanks.. good catch.
[PATCH] PM-WIP-OPP: Fixing wrong target level being passed during Core 
DVFS.
Suggestion on the subject:
could you put it something like the following so that git-am will 
throw away PM-WIP-OPP?
[PATCH] [PM-WIP-OPP] omap3: pm: Fix wrong target level during core dvfs

?
Some suggestion below.

> 
> Signed-off-by: Thara Gopinath <thara@ti.com>
> Cc: Kevin Hilman <khilman@deeprootsystems.com>
> ---
>  arch/arm/mach-omap2/resource34xx.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/resource34xx.c b/arch/arm/mach-omap2/resource34xx.c
> index 3604a38..d2336d8 100644
> --- a/arch/arm/mach-omap2/resource34xx.c
> +++ b/arch/arm/mach-omap2/resource34xx.c
> @@ -463,6 +463,7 @@ int set_opp(struct shared_resource *resp, u32 target_level)
>  	} else if (resp == vdd2_resp) {
>  		unsigned long req_l3_freq;
>  		struct omap_opp *oppx = NULL;
> +		u8 opp;
>  
>  		/* Convert the tput in KiB/s to Bus frequency in MHz */
>  		req_l3_freq = (target_level * 1000)/4;
> @@ -478,10 +479,11 @@ int set_opp(struct shared_resource *resp, u32 target_level)
>  		/* uh uh.. no OPPs?? */
>  		BUG_ON(IS_ERR(oppx));
>  
If you do target_level = 0; here, the entire patch is a oneliner :)

> -		ret = freq_to_opp((u8 *)&target_level, OPP_L3, req_l3_freq);
> +		ret = freq_to_opp(&opp, OPP_L3, req_l3_freq);
>  		/* we dont expect this to fail */
>  		BUG_ON(ret);
>  
> +		target_level = opp;
>  		ret = resource_set_opp_level(VDD2_OPP, target_level, 0);
>  	}
>  	return 0;

-- 
Regards,
Nishanth Menon