Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752479AbcLER2b (ORCPT ); Mon, 5 Dec 2016 12:28:31 -0500 Received: from mail-yw0-f170.google.com ([209.85.161.170]:36770 "EHLO mail-yw0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751913AbcLER2Z (ORCPT ); Mon, 5 Dec 2016 12:28:25 -0500 MIME-Version: 1.0 In-Reply-To: <85f3e098-9566-751e-f201-dddda973f77a@codeaurora.org> References: <1480645942-29912-1-git-send-email-wzz@rock-chips.com> <85f3e098-9566-751e-f201-dddda973f77a@codeaurora.org> From: Sean Paul Date: Mon, 5 Dec 2016 12:28:01 -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: 3426 Lines: 117 On Sun, Dec 4, 2016 at 10:13 PM, Archit Taneja wrote: > > > 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? > Yeah, one could make a case for dev_info (disclaimer: I have a high tolerance for noisy logs), but a warning does seem excessive. Sean > 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