From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:44897) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S8SLq-0001rU-Ve for qemu-devel@nongnu.org; Fri, 16 Mar 2012 04:17:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S8SLl-0004OM-0f for qemu-devel@nongnu.org; Fri, 16 Mar 2012 04:17:30 -0400 Received: from fmmailgate06.web.de ([217.72.192.247]:50596) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S8SLk-0004O8-NV for qemu-devel@nongnu.org; Fri, 16 Mar 2012 04:17:24 -0400 Received: from moweb002.kundenserver.de (moweb002.kundenserver.de [172.19.20.108]) by fmmailgate06.web.de (Postfix) with ESMTP id BC382F226E0 for ; Fri, 16 Mar 2012 09:17:22 +0100 (CET) Message-ID: <4F62F70D.3050103@web.de> Date: Fri, 16 Mar 2012 09:17:17 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <4E859A76.2000808@siemens.com> <201203151912.47455.marek.vasut@gmail.com> <4F6264EF.90709@web.de> <201203160152.55783.marek.vasut@gmail.com> In-Reply-To: <201203160152.55783.marek.vasut@gmail.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig8C320FCFD23D6A8BB38C34FF" Subject: Re: [Qemu-devel] [PATCH 2/2] Drop obsolete nographic timer List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marek Vasut Cc: Blue Swirl , Anthony Liguori , qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig8C320FCFD23D6A8BB38C34FF Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2012-03-16 01:52, Marek Vasut wrote: > Dear Jan Kiszka, >=20 >> On 2012-03-15 19:12, Marek Vasut wrote: >>> Dear Marek Vasut, >>> >>>> Dear Jan Kiszka, >>>> >>>>> On 2012-03-10 07:19, Marek Vasut wrote: >>>>>> Dear Jan Kiszka, >>>>>> >>>>>>> We flush coalesced MMIO in the device models now, and VNC - for w= hich >>>>>>> this was once introduced - is also fine without it as it has its = own >>>>>>> refresh timer. >>>>>>> >>>>>>> Signed-off-by: Jan Kiszka >>>>>>> --- >>>>>>> >>>>>>> vl.c | 13 ------------- >>>>>>> 1 files changed, 0 insertions(+), 13 deletions(-) >>>>>> >>>>>> This patch seems to break QEMU/PXA emulation for me on the ZipitZ2= >>>>>> platform. The serial console became very slow, but only when I typ= e >>>>>> something in. The output from the device to the console is ok. Aft= er >>>>>> reverting this particular one, the console behaves normally. >>>>> >>>>> Removing that timer removal likely just revealed some formerly hidd= en >>>>> bug. Can you share the command line used for starting and some test= >>>>> image? >>>>> >>>>> Jan >>>> >>>> qemu-system-arm -M z2 -pflash flash.img -serial null -serial null >>>> -serial stdio -display none >>>> >>>> flash.img attached (XZ-ed) >>> >>> Bump? >> >> I had a brief look: The guest is apparently polling the uart, IRQ >> delivery is disabled. >=20 > Yes, it is. >=20 >> But it also receives no timer ticks. I haven't >> checked how it progresses, maybe there is some loop counter used. >=20 > What do you mean? How does the timer implementation in pxa-uboot work? = udelay()=20 > calls on the guest (pxa-uboot) simply poll the timer until it reaches c= ertain=20 > value. There's no paralelism going on at all. I'm starting to understand the issue: The serial port can only accept a single byte. Once this arrived, serial_can_receive1 returns 0, and the backend fd is not longer polled by the io-thread. This should change again as soon as the guest read that byte. But qemu_chr_accept_input, which is properly called by the serial device, didn't kick the io-thread in some way. I solved it this way now: diff --git a/qemu-char.c b/qemu-char.c index 9a5be75..a589a84 100644 --- a/qemu-char.c +++ b/qemu-char.c @@ -177,6 +177,7 @@ void qemu_chr_accept_input(CharDriverState *s) { if (s->chr_accept_input) s->chr_accept_input(s); + qemu_notify_event(); } void qemu_chr_fe_printf(CharDriverState *s, const char *fmt, ...) But I'm not yet sure if this is correct. Comments welcome! Jan --------------enig8C320FCFD23D6A8BB38C34FF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk9i9xAACgkQitSsb3rl5xT+OgCgwoQnuY2L18vW4R6XskaxikK6 2u4AnRsODLeP71/rklGWjVdfoI0WljS/ =RJVo -----END PGP SIGNATURE----- --------------enig8C320FCFD23D6A8BB38C34FF--