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[2001:1c00:c1e:bf00:1054:9d19:e0f0:8214]) by smtp.gmail.com with ESMTPSA id q14sm550485eji.63.2021.10.07.03.07.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Oct 2021 03:07:07 -0700 (PDT) From: Hans de Goede To: Lyude Paul , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org References: <20211001225344.1752203-1-lyude@redhat.com> <2b04c75841f4c1661c242a3371b12d52bb0573ef.camel@redhat.com> <6216276e-6998-cb40-3299-81ac03a1f3a9@redhat.com> Message-ID: <1eeaec2b-4ee5-8bfc-3121-239e85ea48dd@redhat.com> Date: Thu, 7 Oct 2021 12:07:07 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <6216276e-6998-cb40-3299-81ac03a1f3a9@redhat.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hdegoede@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Nouveau] [Intel-gfx] [PATCH v2 0/4] drm/dp, drm/i915: Finish basic PWM support for VESA backlight helpers X-BeenThere: nouveau@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Nouveau development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: nouveau-bounces@lists.freedesktop.org Sender: "Nouveau" Hi, On 10/7/21 11:54 AM, Hans de Goede wrote: > Hi, > > On 10/5/21 10:26 PM, Lyude Paul wrote: >> On Sat, 2021-10-02 at 11:14 +0200, Hans de Goede wrote: >>> Hi Lyude, >>> >>> On 10/2/21 12:53 AM, Lyude Paul wrote: >>>> When I originally moved all of the VESA backlight code in i915 into DRM >>>> helpers, one of the things I didn't have the hardware or time for >>>> testing was machines that used a combination of PWM and DPCD in order to >>>> control their backlights. This has since then caused some breakages and >>>> resulted in us disabling DPCD backlight support on such machines. This >>>> works fine, unless you have a machine that actually needs this >>>> functionality for backlight controls to work at all. Additionally, we >>>> will need to support PWM for when we start adding support for VESA's >>>> product (as in the product of multiplication) control mode for better >>>> brightness ranges. >>>> >>>> So - let's finally finish up implementing basic support for these types >>>> of backlights to solve these problems in our DP helpers, along with >>>> implementing support for this in i915. And since digging into this issue >>>> solved the last questions we really had about probing backlights in i915 >>>> for the most part, let's update some of the comments around that as >>>> well! >>> >>> Backlight control is a topic which I'm reasonably familiar with, >>> do you want me to review this series for you ? >> >> Possibly, although I definitely want to make sure that someone from Intel gets >> a chance to review this as well. > > I already expected you would also want someone from Intel to take a look > as well :) > > So to figure out if I have system to test this I ended up taking a close > look at the code, which was a nice learning experience. Interesting how > some panels use a combination of DCPD + pwm/gpio for enable/disable and/or > pwm for brightness level control. > > I wonder though what DCPD still does if pwm is used for both the > enable/disable and brightness-level control ? > > Since I was taking a close look already I decided to do turn this into > a full, the entire set looks good to me: > > Reviewed-by: Hans de Goede > >> I'm more curious if you might happen to have >> any systems that would be able to test this. > > I don't believe I have a system where I can test this, The only systems > which I have which presumably (I did not check) use eDP / DCPD backlight > control are boring ThinkPads with only i915 gfx. Continuing with reading my email I see that you've also posted a v5 with 1 new patch: [PATCH v3 3/5] drm/dp: Disable unsupported features in DP_EDP_BACKLIGHT_MODE_SET_REGISTER That patch looks good to me too, so you may also add my: Reviewed-by: Hans de Goede To that one / to the entire v3 series. Regards, Hans >>>> Changes: >>>> * Fixup docs >>>> * Add patch to stop us from breaking nouveau >>>> >>>> Lyude Paul (4): >>>>   drm/i915: Add support for panels with VESA backlights with PWM >>>>     enable/disable >>>>   drm/nouveau/kms/nv50-: Explicitly check DPCD backlights for aux >>>>     enable/brightness >>>>   drm/dp, drm/i915: Add support for VESA backlights using PWM for >>>>     brightness control >>>>   drm/i915: Clarify probing order in intel_dp_aux_init_backlight_funcs() >>>> >>>>  drivers/gpu/drm/drm_dp_helper.c               | 75 +++++++++++------ >>>>  .../drm/i915/display/intel_dp_aux_backlight.c | 80 ++++++++++++++----- >>>>  drivers/gpu/drm/nouveau/nouveau_backlight.c   |  5 +- >>>>  include/drm/drm_dp_helper.h                   |  7 +- >>>>  4 files changed, 122 insertions(+), 45 deletions(-) >>>> >>> >>