Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754176AbcLBQDg (ORCPT ); Fri, 2 Dec 2016 11:03:36 -0500 Received: from mail-yb0-f175.google.com ([209.85.213.175]:34927 "EHLO mail-yb0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751541AbcLBQDe (ORCPT ); Fri, 2 Dec 2016 11:03:34 -0500 MIME-Version: 1.0 In-Reply-To: References: <1480645942-29912-1-git-send-email-wzz@rock-chips.com> From: Sean Paul Date: Fri, 2 Dec 2016 11:03:09 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] drm/bridge: analogix: Don't return -EINVAL when panel not support PSR in PSR functions To: Archit Taneja 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 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2717 Lines: 85 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. 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