From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755300Ab3CZXim (ORCPT ); Tue, 26 Mar 2013 19:38:42 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:52541 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754665Ab3CZWoH (ORCPT ); Tue, 26 Mar 2013 18:44:07 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Julia Lemire , Dave Airlie Subject: [ 59/98] drm/mgag200: Bug fix: Modified pll algorithm for EH project Date: Tue, 26 Mar 2013 15:42:48 -0700 Message-Id: <20130326224248.651684753@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.rc1.5.g7e0651a In-Reply-To: <20130326224242.449070940@linuxfoundation.org> References: <20130326224242.449070940@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Julia Lemire commit 260b3f1291a75a580d22ce8bfb1499c617272716 upstream. While testing the mgag200 kms driver on the HP ProLiant Gen8, a bug was seen. Once the bootloader would load the selected kernel, the screen would go black. At first it was assumed that the mgag200 kms driver was hanging. But after setting up the grub serial output, it was seen that the driver was being loaded properly. After trying serval monitors, one finaly displayed the message "Frequency Out of Range". By comparing the kms pll algorithm with the previous mgag200 xorg driver pll algorithm, discrepencies were found. Once the kms pll algorithm was modified, the expected pll values were produced. This fix was tested on several monitors of varying native resolutions. Signed-off-by: Julia Lemire Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/mgag200/mgag200_mode.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/drivers/gpu/drm/mgag200/mgag200_mode.c +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c @@ -382,19 +382,19 @@ static int mga_g200eh_set_plls(struct mg m = n = p = 0; vcomax = 800000; vcomin = 400000; - pllreffreq = 3333; + pllreffreq = 33333; delta = 0xffffffff; permitteddelta = clock * 5 / 1000; - for (testp = 16; testp > 0; testp--) { + for (testp = 16; testp > 0; testp >>= 1) { if (clock * testp > vcomax) continue; if (clock * testp < vcomin) continue; for (testm = 1; testm < 33; testm++) { - for (testn = 1; testn < 257; testn++) { + for (testn = 17; testn < 257; testn++) { computed = (pllreffreq * testn) / (testm * testp); if (computed > clock) @@ -404,11 +404,11 @@ static int mga_g200eh_set_plls(struct mg if (tmpdelta < delta) { delta = tmpdelta; n = testn - 1; - m = (testm - 1) | ((n >> 1) & 0x80); + m = (testm - 1); p = testp - 1; } if ((clock * testp) >= 600000) - p |= 80; + p |= 0x80; } } }