From: Dirk Brandewie <[email protected]> Commit 21855ff5 intel_pstate: Set turbo VID for BayTrail introduced setting the turbo VID which is required to prevent a machine check on some Baytrail SKUs under heavy graphics based workloads. The docmumentation update that brought the requirement to light also changed the bit mask used for enumerating P state and VID values from 0x7f to 0x3f.
This change returns the mask value to 0x7f. Tested with the Intel NUC DN2820FYK, BIOS version FYBYT10H.86A.0034.2014.0513.1413 with v3.16-rc1 and v3.14.8 kernel versions. Reported-by: Rune Reterson <[email protected]> Reported-by: Eric Eickmeyer <[email protected]> Tested-by: Rune Reterson <[email protected]> Tested-by: Eric Eickmeyer <[email protected]> References: https://bugzilla.kernel.org/show_bug.cgi?id=77951 Cc: Cc: Stable <[email protected]> [3.13+] Signed-off-by: Dirk Brandewie <[email protected]> --- drivers/cpufreq/intel_pstate.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 924bb2d..74376d6 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -357,21 +357,21 @@ static int byt_get_min_pstate(void) { u64 value; rdmsrl(BYT_RATIOS, value); - return (value >> 8) & 0x3F; + return (value >> 8) & 0x7F; } static int byt_get_max_pstate(void) { u64 value; rdmsrl(BYT_RATIOS, value); - return (value >> 16) & 0x3F; + return (value >> 16) & 0x7F; } static int byt_get_turbo_pstate(void) { u64 value; rdmsrl(BYT_TURBO_RATIOS, value); - return value & 0x3F; + return value & 0x7F; } static void byt_set_pstate(struct cpudata *cpudata, int pstate) @@ -405,8 +405,8 @@ static void byt_get_vid(struct cpudata *cpudata) rdmsrl(BYT_VIDS, value); - cpudata->vid.min = int_tofp((value >> 8) & 0x3f); - cpudata->vid.max = int_tofp((value >> 16) & 0x3f); + cpudata->vid.min = int_tofp((value >> 8) & 0x7f); + cpudata->vid.max = int_tofp((value >> 16) & 0x7f); cpudata->vid.ratio = div_fp( cpudata->vid.max - cpudata->vid.min, int_tofp(cpudata->pstate.max_pstate - -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
