Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756941Ab2JZHo5 (ORCPT ); Fri, 26 Oct 2012 03:44:57 -0400 Received: from mail-oa0-f46.google.com ([209.85.219.46]:44072 "EHLO mail-oa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756862Ab2JZHoy (ORCPT ); Fri, 26 Oct 2012 03:44:54 -0400 MIME-Version: 1.0 In-Reply-To: <508A3D32.6090101@ti.com> References: <1349246100-7477-1-git-send-email-prabhakar.lad@ti.com> <506C158D.4000906@ti.com> <506D3704.4060102@ti.com> <508A3D32.6090101@ti.com> From: Prabhakar Lad Date: Fri, 26 Oct 2012 13:14:33 +0530 Message-ID: Subject: Re: [PATCH] ARM: davinci: dm644x: fix out range signal for ED To: Sekhar Nori Cc: DLOS , Manjunath Hadli , VGER , LAK , "Lad, Prabhakar" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2966 Lines: 74 Sekhar, On Fri, Oct 26, 2012 at 1:05 PM, Sekhar Nori wrote: > On 10/4/2012 7:23 PM, Prabhakar Lad wrote: >> Sekhar >> >> On Thu, Oct 4, 2012 at 12:43 PM, Sekhar Nori wrote: >>> On 10/4/2012 10:22 AM, Prabhakar Lad wrote: >>>> Hi Sekhar, >>>> >>>> On Wed, Oct 3, 2012 at 4:08 PM, Sekhar Nori wrote: >>>>> On 10/3/2012 12:05 PM, Prabhakar wrote: >>>>>> From: Lad, Prabhakar >>>>>> >>>>>> while testing display on dm644x, for ED out-range signals >>>>>> was observed. This patch fixes appropriate clock setting >>>>>> for ED. >>>>> >>>>> Can you please clarify what you mean by "out range signal"? Are there >>>>> any user visible artifacts on the display? What was the clock being >>>>> provided earlier and what is the value after this patch? >>>>> >>>>> Also, is the issue severe enough that this patch should be applied to >>>>> stable tree as well? >>>>> >>>> Ideally a clock of 54Mhz is required for enhanced definition to >>>> work, which it was actually set to but while testing I noticed >>>> out-of-range signal. The out-of-range signal is often caused >>>> when the field rate is above the rate that the television will handle. >>>> When this is the case the TV or monitor displays "Out-Of-Range Signal". >>>> >>>> Reducing the clock fixed it. now the clock is set to 27Mhz. >>> >>> So, is the requirement for ED 54MHz or lower? Still trying to explain >>> myself how 27MHz is working where a 54MHz is required. I guess there is >>> also a lower limit on what the frequency should be? >>> >> Ideally its 54Mhz, but I see in the datasheet for AD7342/3 [1] it can also >> work at 27Mhz too. > > So, based on this discussion I think a better description would be: > > " > Fix the video clock setting when custom timings are used with pclock <= > 27MHz. Existing clock selection uses PLL2 mode which results in a 54MHz > clock where as using the MXI mode results in a 27MHz clock (which is the > one actually desired). > > This affects the Enhanced Definition (ED) support on DM644x. Without > this patch, out-range signals errors are were observed on the TV. An > out-of-range signal is often caused when the field rate is above the > rate that the television will handle. > " > > Is this accurate? In future, please try to be descriptive in patch > description as it will help understand what the patch is doing and why > (which in turn will lead to the patch getting accepted faster). > Looks good. I'll make sure to have descriptive commit message hence forth. > Also I assume you need this patch in v3.7? Or can I send it for v3.8? > Since its a fix it would be good if its queued for v3.7. Regards, --Prabhakar > Thanks, > Sekhar -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/