Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751644AbcLEDNy (ORCPT ); Sun, 4 Dec 2016 22:13:54 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:59116 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751530AbcLEDNs (ORCPT ); Sun, 4 Dec 2016 22:13:48 -0500 DMARC-Filter: OpenDMARC Filter v1.3.1 smtp.codeaurora.org 539E460CE3 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=pass smtp.mailfrom=architt@codeaurora.org Subject: Re: [PATCH] drm/bridge: analogix: Don't return -EINVAL when panel not support PSR in PSR functions To: Sean Paul References: <1480645942-29912-1-git-send-email-wzz@rock-chips.com> Cc: zain wang , Daniel Vetter , Inki Dae , David Airlie , Tomeu Vizoso , Mika Kahola , =?UTF-8?Q?St=c3=a9phane_Marchesin?= , Tomasz Figa , Doug Anderson , Thierry Reding , Krzysztof Kozlowski , Heiko Stuebner , Jingoo Han , Javier Martinez Canillas , Linux Kernel Mailing List , dri-devel , linux-samsung-soc , linux-rockchip@lists.infradead.org From: Archit Taneja Message-ID: <85f3e098-9566-751e-f201-dddda973f77a@codeaurora.org> Date: Mon, 5 Dec 2016 08:43:38 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3063 Lines: 98 On 12/02/2016 09:33 PM, Sean Paul wrote: > On Thu, Dec 1, 2016 at 10:54 PM, Archit Taneja wrote: >> Hi, >> >> On 12/02/2016 08:02 AM, zain wang wrote: >>> >>> We will ignored PSR setting if panel not support it. So, in this case, we >>> should >>> return from analogix_dp_enable/disable_psr() without any error code. >>> Let's retrun 0 instead of -EINVAL when panel not support PSR in >>> analogix_dp_enable/disable_psr(). >>> >>> Signed-off-by: zain wang >>> --- >>> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 6 ++++-- >>> 1 file changed, 4 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c >>> b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c >>> index 6e0447f..0cb3695 100644 >>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c >>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c >>> @@ -112,7 +112,7 @@ int analogix_dp_enable_psr(struct device *dev) >>> struct edp_vsc_psr psr_vsc; >>> >>> if (!dp->psr_support) >>> - return -EINVAL; >>> + return 0; >> >> >> Looking at the rockchip analogix dp code, in analogix_dp_psr_set, the worker >> that calls >> analogix_dp_enable/disable_psr isn't even if psr isn't enabled. So, the >> bridge funcs >> shouldn't be called in the first place. I think the error handling is fine >> to have >> here. >> > > Hi Archit, > > This was my first impression, too, and the complexity of the various > psr abstraction layers don't help :) > > However, this code path will be hit if the source supports psr, but > the sink doesn't. The rockchip_drm_psr code doesn't know if the sink > supports psr, so it will end up calling this. Okay, thanks for the explanation. The dev_warn() below still seems unnecessary, right? Archit > > Sean > > >>> >>> /* Prepare VSC packet as per EDP 1.4 spec, Table 6.9 */ >>> memset(&psr_vsc, 0, sizeof(psr_vsc)); >>> @@ -135,7 +135,7 @@ int analogix_dp_disable_psr(struct device *dev) >>> struct edp_vsc_psr psr_vsc; >>> >>> if (!dp->psr_support) >>> - return -EINVAL; >>> + return 0; >>> >>> /* Prepare VSC packet as per EDP 1.4 spec, Table 6.9 */ >>> memset(&psr_vsc, 0, sizeof(psr_vsc)); >>> @@ -878,6 +878,8 @@ static void analogix_dp_commit(struct >>> analogix_dp_device *dp) >>> dp->psr_support = analogix_dp_detect_sink_psr(dp); >>> if (dp->psr_support) >>> analogix_dp_enable_sink_psr(dp); >>> + else >>> + dev_warn(dp->dev, "Sink not support PSR\n"); >> >> >> This doesn't seem beneficial either. There seems to be a debug >> print already in analogix_dp_detect_sink_psr which reports PSR >> related info. >> >> Archit >> >>> } >>> >>> /* >>> >> >> -- >> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, >> a Linux Foundation Collaborative Project -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project