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Mon, 27 Jul 2020 11:18:33 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06RBColY098984; Mon, 27 Jul 2020 11:18:32 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3020.oracle.com with ESMTP id 32hu5qqu0k-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 27 Jul 2020 11:18:32 +0000 Received: from abhmp0012.oracle.com (abhmp0012.oracle.com [141.146.116.18]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 06RBIV8V015384; Mon, 27 Jul 2020 11:18:31 GMT Received: from mwanda (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 27 Jul 2020 04:18:30 -0700 Date: Mon, 27 Jul 2020 14:18:25 +0300 From: To: hyun.kwon@xilinx.com Subject: [bug report] drm: xlnx: DRM/KMS driver for Xilinx ZynqMP DisplayPort Subsystem Message-ID: <20200727111825.GB389488@mwanda> MIME-Version: 1.0 Content-Disposition: inline X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9694 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 phishscore=0 bulkscore=0 malwarescore=0 suspectscore=3 spamscore=0 mlxlogscore=839 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007270083 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9694 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 bulkscore=0 mlxlogscore=839 lowpriorityscore=0 malwarescore=0 clxscore=1011 mlxscore=0 impostorscore=0 phishscore=0 adultscore=0 suspectscore=3 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007270083 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dri-devel@lists.freedesktop.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hello Hyun Kwon, The patch d76271d22694: "drm: xlnx: DRM/KMS driver for Xilinx ZynqMP DisplayPort Subsystem" from Jul 7, 2018, leads to the following static checker warning: drivers/gpu/drm/xlnx/zynqmp_dp.c:594 zynqmp_dp_mode_configure() error: iterator underflow 'bws' (-1)-2 drivers/gpu/drm/xlnx/zynqmp_dp.c 566 static int zynqmp_dp_mode_configure(struct zynqmp_dp *dp, int pclock, 567 u8 current_bw) 568 { 569 int max_rate = dp->link_config.max_rate; 570 u8 bws[3] = { DP_LINK_BW_1_62, DP_LINK_BW_2_7, DP_LINK_BW_5_4 }; 571 u8 max_lanes = dp->link_config.max_lanes; 572 u8 max_link_rate_code = drm_dp_link_rate_to_bw_code(max_rate); 573 u8 bpp = dp->config.bpp; 574 u8 lane_cnt; 575 s8 i; 576 577 if (current_bw == DP_LINK_BW_1_62) { 578 dev_err(dp->dev, "can't downshift. already lowest link rate\n"); 579 return -EINVAL; 580 } 581 582 for (i = ARRAY_SIZE(bws) - 1; i >= 0; i--) { ^^^^^^ This exits with i == -1. 583 if (current_bw && bws[i] >= current_bw) 584 continue; 585 586 if (bws[i] <= max_link_rate_code) 587 break; 588 } 589 590 for (lane_cnt = 1; lane_cnt <= max_lanes; lane_cnt <<= 1) { 591 int bw; 592 u32 rate; 593 594 bw = drm_dp_bw_code_to_link_rate(bws[i]); ^^^^^^ Potential negative array offset. 595 rate = zynqmp_dp_max_rate(bw, lane_cnt, bpp); 596 if (pclock <= rate) { 597 dp->mode.bw_code = bws[i]; 598 dp->mode.lane_cnt = lane_cnt; 599 dp->mode.pclock = pclock; 600 return dp->mode.bw_code; 601 } 602 } 603 604 dev_err(dp->dev, "failed to configure link values\n"); 605 606 return -EINVAL; 607 } regards, dan carpenter _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel