mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: jeremy.compostella@intel.com (Compostella, Jeremy)
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org, "Kumar P\,
	Mahesh" <mahesh.kumar.p@intel.com>, "Afantenos\,
	Marie Cecile" <marie.cecile.afantenos@intel.com>,
	"Jeremy Compostell" <jeremy.compostella@gmail.com>
Subject: [PATCH] x86: add the X86_FEATURE_NONSTOP_TSC_S3 cpu capability to new cpu
Date: Thu, 23 Oct 2014 19:27:26 +0200	[thread overview]
Message-ID: <87ppdik875.fsf@jcompost-MOBL1.tl.intel.com> (raw)

New Intel Atom processors (Baytrail and Cherryview), have a TSC that won't stop
in S3 state, say the TSC value won't be reset to 0 after resume.  This feature
makes TSC a more reliable clocksource and could benefit the timekeeping code
during system suspend/resume cycle.

Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
---
 arch/x86/kernel/cpu/intel.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 1ef4562..8af195e 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -92,11 +92,16 @@ static void early_init_intel(struct cpuinfo_x86 *c)
 			set_sched_clock_stable();
 	}
 
-	/* Penwell and Cloverview have the TSC which doesn't sleep on S3 */
+	/*
+	 * Penwell, Cloverview, Valleyview and Cherryview have the TSC
+	 * which doesn't sleep on S3.
+	 */
 	if (c->x86 == 6) {
 		switch (c->x86_model) {
 		case 0x27:	/* Penwell */
 		case 0x35:	/* Cloverview */
+		case 0x37:	/* Valleyview */
+		case 0x4C:	/* Cherryview */
 			set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC_S3);
 			break;
 		default:
-- 
1.9.1


                 reply	other threads:[~2014-10-23 17:28 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=87ppdik875.fsf@jcompost-MOBL1.tl.intel.com \
    --to=jeremy.compostella@intel.com \
    --cc=hpa@zytor.com \
    --cc=jeremy.compostella@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mahesh.kumar.p@intel.com \
    --cc=marie.cecile.afantenos@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

Powered by JetHome