Messages in this thread | | | Subject | Re: [PATCH v2 2/2] ACPI/PPTT: Handle architecturally unknown cache types | From | Jeffrey Hugo <> | Date | Mon, 17 Sep 2018 16:46:27 -0600 |
| |
On 9/17/2018 10:17 AM, Sudeep Holla wrote: > > > On 14/09/18 17:28, Jeffrey Hugo wrote: >> The type of a cache might not be specified by architectural mechanisms (ie >> system registers), but its type might be specified in the PPTT. In this >> case, we should populate the type of the cache, rather than leave it >> undefined. >> >> This fixes the issue where the cacheinfo driver will not populate sysfs >> for such caches, resulting in the information missing from utilities like >> lstopo and lscpu, thus degrading the user experience. >> >> Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table parsing) >> Reported-by: Vijaya Kumar K <vkilari@codeaurora.org> >> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org> >> --- >> drivers/acpi/pptt.c | 15 +++++++++++---- >> 1 file changed, 11 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c >> index d1e26cb..bb00ed9 100644 >> --- a/drivers/acpi/pptt.c >> +++ b/drivers/acpi/pptt.c >> @@ -402,11 +402,18 @@ static void update_cache_properties(struct cacheinfo *this_leaf, >> } >> } >> /* >> - * If the above flags are valid, and the cache type is NOCACHE >> - * update the cache type as well. >> + * If cache type is NOCACHE, then the cache hasn't been specified >> + * via other mechanisms. Update the type if either the cache has >> + * been fully specified in PPTT, or a cache type has been provided. >> + * >> + * Note, we assume such caches are unified based on conventional system >> + * design and known examples. Significant work is required elsewhere to >> + * fully support data/instruction only type caches which are only >> + * specified in PPTT. >> */ >> - if (this_leaf->type == CACHE_TYPE_NOCACHE && >> - valid_flags == PPTT_CHECKED_ATTRIBUTES) >> + if ((this_leaf->type == CACHE_TYPE_NOCACHE) && >> + (valid_flags == PPTT_CHECKED_ATTRIBUTES || >> + found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)) >> this_leaf->type = CACHE_TYPE_UNIFIED; > > I thought I did mention that we can drop the valid_flags altogether > unless Jeremy has reasons not to. >
You suggested that perhaps that could be the case. It seemed like an open question to me. I'm at Linaro Connect without access to the device this week, so I guess someone has roughly a week to chime in that the valid flags should be kept, otherwise I'll try a v3 with them removed.
-- Jeffrey Hugo Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
| |