From patchwork Fri Jan 22 20:51:03 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Snow X-Patchwork-Id: 8092891 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id B783DBEEED for ; Fri, 22 Jan 2016 20:56:18 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4F5172058C for ; Fri, 22 Jan 2016 20:56:17 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7B695204DE for ; Fri, 22 Jan 2016 20:56:16 +0000 (UTC) Received: from localhost ([::1]:55498 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aMikh-0003h8-Sc for patchwork-qemu-devel@patchwork.kernel.org; Fri, 22 Jan 2016 15:56:15 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34249) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aMifw-0002U5-Nz for qemu-devel@nongnu.org; Fri, 22 Jan 2016 15:51:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aMifu-0003jM-6D for qemu-devel@nongnu.org; Fri, 22 Jan 2016 15:51:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38024) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aMifq-0003go-V0; Fri, 22 Jan 2016 15:51:15 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (Postfix) with ESMTPS id 811D43B12D4; Fri, 22 Jan 2016 20:51:14 +0000 (UTC) Received: from scv.usersys.redhat.com (vpn-56-29.rdu2.redhat.com [10.10.56.29]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u0MKp574022541; Fri, 22 Jan 2016 15:51:13 -0500 From: John Snow To: qemu-block@nongnu.org Date: Fri, 22 Jan 2016 15:51:03 -0500 Message-Id: <1453495865-9649-11-git-send-email-jsnow@redhat.com> In-Reply-To: <1453495865-9649-1-git-send-email-jsnow@redhat.com> References: <1453495865-9649-1-git-send-email-jsnow@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, John Snow , armbru@redhat.com, qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH v5 10/12] fdc: rework pick_geometry X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This one is the crazy one. fd_revalidate currently uses pick_geometry to tell if the diskette geometry has changed upon an eject/insert event, but it won't allow us to insert a 1.44MB diskette into a 2.88MB drive. This is inflexible. The new algorithm applies a new heuristic to guessing disk geometries that allows us to switch diskette types as long as the physical size matches before falling back to the old heuristic. The old one is roughly: - If the size (sectors) and type matches, choose it. - Fall back to the first geometry that matched our type. The new one is: - If the size (sectors) and type matches, choose it. - If the size (sectors) and physical size match, choose it. - If the size (sectors) matches at all, choose it begrudgingly. - Fall back to the first geometry that matched our type. Signed-off-by: John Snow Reviewed-by: Eric Blake --- hw/block/fdc.c | 72 ++++++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 52 insertions(+), 20 deletions(-) diff --git a/hw/block/fdc.c b/hw/block/fdc.c index e51154b..6e0c5fc 100644 --- a/hw/block/fdc.c +++ b/hw/block/fdc.c @@ -125,7 +125,6 @@ static const FDFormat fd_formats[] = { { FLOPPY_DRIVE_TYPE_NONE, -1, -1, 0, 0, }, }; -__attribute__((__unused__)) static FDriveSize drive_size(FloppyDriveType drive) { switch (drive) { @@ -284,45 +283,78 @@ static int pick_geometry(FDrive *drv) BlockBackend *blk = drv->blk; const FDFormat *parse; uint64_t nb_sectors, size; - int i, first_match, match; + int i; + int match, size_match, type_match; + bool magic = drv->drive == FLOPPY_DRIVE_TYPE_AUTO; /* We can only pick a geometry if we have a diskette. */ if (!drv->media_inserted || drv->drive == FLOPPY_DRIVE_TYPE_NONE) { return -1; } + /* We need to determine the likely geometry of the inserted medium. + * In order of preference, we look for: + * (1) The same drive type and number of sectors, + * (2) The same diskette size and number of sectors, + * (3) The same drive type. + * + * In all cases, matches that occur higher in the drive table will take + * precedence over matches that occur later in the table. + */ blk_get_geometry(blk, &nb_sectors); - match = -1; - first_match = -1; + match = size_match = type_match = -1; for (i = 0; ; i++) { parse = &fd_formats[i]; if (parse->drive == FLOPPY_DRIVE_TYPE_NONE) { break; } - if (drv->drive == parse->drive || - drv->drive == FLOPPY_DRIVE_TYPE_AUTO) { - size = (parse->max_head + 1) * parse->max_track * - parse->last_sect; - if (nb_sectors == size) { - match = i; - break; + size = (parse->max_head + 1) * parse->max_track * parse->last_sect; + if (nb_sectors == size) { + if (magic || parse->drive == drv->drive) { + /* (1) perfect match -- nb_sectors and drive type */ + goto out; + } else if (drive_size(parse->drive) == drive_size(drv->drive)) { + /* (2) size match -- nb_sectors and physical medium size */ + match = (match == -1) ? i : match; + } else { + /* This is suspicious -- Did the user misconfigure? */ + size_match = (size_match == -1) ? i : size_match; } - if (first_match == -1) { - first_match = i; + } else if (type_match == -1) { + if ((parse->drive == drv->drive) || + (magic && (parse->drive == get_fallback_drive_type(drv)))) { + /* (3) type match -- nb_sectors mismatch, but matches the type + * specified explicitly by the user, or matches the fallback + * default type when using the drive autodetect mechanism */ + type_match = i; } } } + + /* No exact match found */ if (match == -1) { - if (first_match == -1) { - error_setg(&error_abort, "No candidate geometries present in table " - " for floppy drive type '%s'", - FloppyDriveType_lookup[drv->drive]); - } else { - match = first_match; + if (size_match != -1) { + parse = &fd_formats[size_match]; + FLOPPY_DPRINTF("User requested floppy drive type '%s', " + "but inserted medium appears to be a " + "%d sector '%s' type\n", + FloppyDriveType_lookup[drv->drive], + nb_sectors, + FloppyDriveType_lookup[parse->drive]); } - parse = &fd_formats[match]; + match = type_match; } + /* No match of any kind found -- fd_format is misconfigured, abort. */ + if (match == -1) { + error_setg(&error_abort, "No candidate geometries present in table " + " for floppy drive type '%s'", + FloppyDriveType_lookup[drv->drive]); + } + + parse = &(fd_formats[match]); + + out: if (parse->max_head == 0) { drv->flags &= ~FDISK_DBL_SIDES; } else {