From patchwork Mon Apr 30 13:46:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maarten Lankhorst X-Patchwork-Id: 10371827 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0CDBB6038F for ; Mon, 30 Apr 2018 13:47:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F11B628606 for ; Mon, 30 Apr 2018 13:47:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E598B28B10; Mon, 30 Apr 2018 13:47:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id AEF0828606 for ; Mon, 30 Apr 2018 13:47:00 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1E74A6E30B; Mon, 30 Apr 2018 13:46:39 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mblankhorst.nl (mblankhorst.nl [141.105.120.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 50E886E2EF; Mon, 30 Apr 2018 13:46:23 +0000 (UTC) From: Maarten Lankhorst To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Date: Mon, 30 Apr 2018 15:46:07 +0200 Message-Id: <20180430134611.50988-2-maarten.lankhorst@linux.intel.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180430134611.50988-1-maarten.lankhorst@linux.intel.com> References: <20180430134611.50988-1-maarten.lankhorst@linux.intel.com> Subject: [Intel-gfx] [PATCH 1/5] drm/rect: Round above 1 << 16 upwards to correct scale calculation functions. X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP When calculating limits we want to be as pessimistic as possible, so we have to explicitly say whether we want to round up or down to accurately calculate whether we are below min_scale or above max_scale. Signed-off-by: Maarten Lankhorst --- drivers/gpu/drm/drm_rect.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c index 9817c1445ba9..b179c7c73cc5 100644 --- a/drivers/gpu/drm/drm_rect.c +++ b/drivers/gpu/drm/drm_rect.c @@ -106,7 +106,10 @@ static int drm_calc_scale(int src, int dst) if (dst == 0) return 0; - scale = src / dst; + if (src > (dst << 16)) + return DIV_ROUND_UP(src, dst); + else + scale = src / dst; return scale; } @@ -121,6 +124,9 @@ static int drm_calc_scale(int src, int dst) * Calculate the horizontal scaling factor as * (@src width) / (@dst width). * + * If the scale is below 1 << 16, round down, if above up. This will + * calculate the scale with the most pessimistic limit calculation. + * * RETURNS: * The horizontal scaling factor, or errno of out of limits. */ @@ -152,6 +158,9 @@ EXPORT_SYMBOL(drm_rect_calc_hscale); * Calculate the vertical scaling factor as * (@src height) / (@dst height). * + * If the scale is below 1 << 16, round down, if above up. This will + * calculate the scale with the most pessimistic limit calculation. + * * RETURNS: * The vertical scaling factor, or errno of out of limits. */ @@ -189,6 +198,9 @@ EXPORT_SYMBOL(drm_rect_calc_vscale); * If the calculated scaling factor is above @max_vscale, * decrease the height of rectangle @src to compensate. * + * If the scale is below 1 << 16, round down, if above up. This will + * calculate the scale with the most pessimistic limit calculation. + * * RETURNS: * The horizontal scaling factor. */ @@ -239,6 +251,9 @@ EXPORT_SYMBOL(drm_rect_calc_hscale_relaxed); * If the calculated scaling factor is above @max_vscale, * decrease the height of rectangle @src to compensate. * + * If the scale is below 1 << 16, round down, if above up. This will + * calculate the scale with the most pessimistic limit calculation. + * * RETURNS: * The vertical scaling factor. */