From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4648A597.70600@domain.hid> Date: Mon, 14 May 2007 20:08:23 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <46478F98.1040101@domain.hid> In-Reply-To: <46478F98.1040101@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigF473707B0652D39627D8CC4A" Sender: jan.kiszka@domain.hid Subject: Re: [Xenomai-core] [BUG] pit clocksource broken under Xenomai List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenomai-core , adeos-main This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigF473707B0652D39627D8CC4A Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Jan Kiszka wrote: > Hi, >=20 > just checked on real hardware (found in qemu originally): >=20 > When Linux uses the pit clocksource AND Xenomai is attached, the system= > time no longer makes progress. Observed under 2.6.20 with 1.7-03 and > newer patches, Xenomai trunk. >=20 > I guess not many people will be affected by this and I'm lacking time t= o > debug, so I'm just dumping the report and running away... Somehow I hate open issues... I recalled some private thread with you, Philippe, about this particular line in pid_read(). A look at it again revealed the reason for this bug. Jan PS: pending_patches++ ;) --- arch/i386/kernel/i8253.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) Index: linux-2.6.20/arch/i386/kernel/i8253.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- linux-2.6.20.orig/arch/i386/kernel/i8253.c +++ linux-2.6.20/arch/i386/kernel/i8253.c @@ -47,7 +47,8 @@ static cycle_t pit_read(void) =20 #ifdef CONFIG_IPIPE if (!__ipipe_pipeline_head_p(ipipe_root_domain)) - return 0; /* We don't really own the PIT. */ + /* We don't own the PIT, fall back to jiffies. */ + return (cycle_t)(jiffies * LATCH); #endif /* CONFIG_IPIPE */ =20 spin_lock_irqsave(&i8253_lock, flags); --------------enigF473707B0652D39627D8CC4A Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGSKWXniDOoMHTA+kRArdGAJ9qYDToVQ6lfyIuqeGHP/nRRYhfwgCdFosO 4KTyWwe0emxXJk0EVAe9cBI= =KtWU -----END PGP SIGNATURE----- --------------enigF473707B0652D39627D8CC4A--