From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1JlWKP-0001RC-Qh for qemu-devel@nongnu.org; Mon, 14 Apr 2008 17:35:05 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1JlWKL-0001OI-QS for qemu-devel@nongnu.org; Mon, 14 Apr 2008 17:35:05 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1JlWKL-0001O2-JX for qemu-devel@nongnu.org; Mon, 14 Apr 2008 17:35:01 -0400 Received: from fmmailgate03.web.de ([217.72.192.234]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1JlWKK-0006Pg-S3 for qemu-devel@nongnu.org; Mon, 14 Apr 2008 17:35:01 -0400 Received: from smtp05.web.de (fmsmtp05.dlan.cinetic.de [172.20.4.166]) by fmmailgate03.web.de (Postfix) with ESMTP id 65636D716A61 for ; Mon, 14 Apr 2008 23:34:58 +0200 (CEST) Received: from [88.64.24.193] (helo=[192.168.1.198]) by smtp05.web.de with asmtp (TLSv1:AES256-SHA:256) (WEB.DE 4.109 #226) id 1JlWKH-0007Jj-00 for qemu-devel@nongnu.org; Mon, 14 Apr 2008 23:34:57 +0200 Message-ID: <4803CE00.7070809@web.de> Date: Mon, 14 Apr 2008 23:34:56 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <4801C476.3040509@web.de> <4803AED9.7010001@web.de> In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig95DC0C6EBF60D070D43268A5" Sender: jan.kiszka@web.de Subject: [Qemu-devel] Re: [PATCH 2/2] 8250: Customized base baudrate Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig95DC0C6EBF60D070D43268A5 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable andrzej zaborowski wrote: > On 14/04/2008, Jan Kiszka wrote: >> andrzej zaborowski wrote: >> > On 13/04/2008, Jan Kiszka wrote: >> >>>> --- a/hw/omap1.c >> >> +++ b/hw/omap1.c >> >> @@ -1734,7 +1734,8 @@ struct omap_uart_s *omap_uart_init(targe >> >> struct omap_uart_s *s =3D (struct omap_uart_s *) >> >> qemu_mallocz(sizeof(struct omap_uart_s)); >> >> if (chr) >> >> - s->serial =3D serial_mm_init(base, 2, irq, chr, 1); >> >> + s->serial =3D >> >> + serial_mm_init(base, 2, irq, omap_clk_getrate(clk)/1= 6, chr, 1); >> > >> > Yes, this should be correct. >> >> While typing those line I wondered if it is possible and reasonable th= at >> a guest changes this clock rate during runtime? In that case, the >> perfect, but probably much more complex solution would be to track th= ose >> changes also with the serial emulation... >=20 > Yes, UART1 and UART3 (I think) can switch between 48MHz (dpll) and > 16MHz clock domains on OMAP1 and the guest has control over this (and > the characters flow indeed slows down three times when you switch to > 16MHz on the real hw). omap_clk.c allows a peripheral to register for > notifications of rate change for a particular clock. I don't think > it's worth bothering too much because anything that depends on the > timing of QEMU will likely have problems anyway. Well, depends. The baudrate set by the guest is also propagated to the host tty which is attached to that virtual channel. If that tty bothers about baudrate, you will have real impact. Besides this, my patch 1/2 makes use of the baudrate to emulate more realistic output (IRQ) rates. Jan --------------enig95DC0C6EBF60D070D43268A5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFIA84AniDOoMHTA+kRAn7YAJ9ZXKsPGN6cDz0oLcgObu13T/I5nQCfTAlz wPigz5GeB8rCYjMkBuOwmNI= =EYrZ -----END PGP SIGNATURE----- --------------enig95DC0C6EBF60D070D43268A5--