From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60348) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wjtfh-00024u-BI for qemu-devel@nongnu.org; Mon, 12 May 2014 13:05:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WjtfX-0007XP-45 for qemu-devel@nongnu.org; Mon, 12 May 2014 13:05:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33006) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WjtfW-0007XC-SE for qemu-devel@nongnu.org; Mon, 12 May 2014 13:05:39 -0400 Message-ID: <5370FF54.2080808@redhat.com> Date: Mon, 12 May 2014 11:05:24 -0600 From: Eric Blake MIME-Version: 1.0 References: <1399630869-920-1-git-send-email-arei.gonglei@huawei.com> <20140509111807.GA22335@work-vm> <1399636479.5213.56.camel@nilsson.home.kraxel.org> In-Reply-To: <1399636479.5213.56.camel@nilsson.home.kraxel.org> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="HufuKhm5GSXuC2wJcMO8MnHl1nUqr6F5Q" Subject: Re: [Qemu-devel] [PATCH] cirrus_vga: adding sanity check for vram size List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann , "Dr. David Alan Gilbert" Cc: weidong.huang@huawei.com, mst@redhat.com, "libvir-list@redhat.com" , qemu-devel@nongnu.org, arei.gonglei@huawei.com, pbonzini@redhat.com, afaerber@suse.de This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --HufuKhm5GSXuC2wJcMO8MnHl1nUqr6F5Q Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable [adding libvirt] On 05/09/2014 05:54 AM, Gerd Hoffmann wrote: > Hi, >=20 >> virt-manager/libvirt seems to default to 9 MByte of Vram for cirrus, >> so this would break a lot of setups. >=20 > It wouldn't. libvirt sticks that into the xml, but it doesn't set any > qemu parameters. The libvirt parameter actually predates the qemu > property for setting the size. >=20 Then we should probably re-evaluate what libvirt does with the parameters, which avoids breaking any guest that happens to be pre-existing with the odd 9MB sizing in the XML. >> Looking at datasheets on the web seems to say the chips actually went >> down to 1 MB or less. >=20 > I have my doubts we emulate that correctly (register telling the guest > how much memory is actually there etc.). Also it is pretty much useles= s > these days, even the 4MB imply serious constrains when FullHD displays > are commonplace. Newer cirrus drivers such as the kernel's drm driver > are specifically written to qemu's cirrus cards, I have my doubs that > they are prepared to handle 1MB cirrus cards correctly. >=20 > Bottom line: Allowing less than 4MB is asking for trouble for no good > reason ;) >=20 > cheers, > Gerd >=20 >=20 >=20 >=20 >=20 --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --HufuKhm5GSXuC2wJcMO8MnHl1nUqr6F5Q 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 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJTcP9UAAoJEKeha0olJ0NqWxwH/1klvSNKeP4FSI9bayISFFjC CLdJBe7/IqyKm63HtWSQvVsoS+fj8A5ZxL4Ym+ZDz/6uqKitQbEjwlYhsHHgDLpa yXLzXpf+b/YGbj5RB3fgfjUiY788U2SUFJNP3GL2KyiUQhGlHwzF9OIUIHSbKkkK FOL7pwXtwobPDW41b1zddCPYuspId2eUjJ+h2ksR67qtA9Com1tbK/6+qObZa+d/ +PfsSOUBJ9RORDsa9EEKp0/GIvP7qyBGaLXQk7tXPkCEd6jf5mvzhU9zvSP2ySq6 ofDxwPrs/ZbRWi+1rat9efoTHyPDwlcWza/zdMnZCSykmUl9kqR75XKSZhyh8Bg= =U6Wz -----END PGP SIGNATURE----- --HufuKhm5GSXuC2wJcMO8MnHl1nUqr6F5Q--