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@xxxxxx>
Cc: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
---
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
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