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Wed, 06 Aug 2025 03:40:00 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHs/OHoirDrVPeMNrslzB+S2OHot+QToIGzIuPvUCTVFUcXivoOOkUtzhYR5Dm3Rusx+t0sVw== X-Received: by 2002:a05:6a20:72a5:b0:240:1d13:ccc1 with SMTP id adf61e73a8af0-24033036dfamr3237229637.11.1754476799836; Wed, 06 Aug 2025 03:39:59 -0700 (PDT) Received: from [10.92.206.236] ([202.46.23.19]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-76bccfd026dsm15164022b3a.95.2025.08.06.03.39.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 06 Aug 2025 03:39:59 -0700 (PDT) Message-ID: Date: Wed, 6 Aug 2025 16:09:52 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 01/38] drm/msm/dp: split msm_dp_panel_read_sink_caps() into two parts and drop panel drm_edid To: Yongxing Mou Cc: Rob Clark , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , David Airlie , Simona Vetter , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org, Abhinav Kumar References: <20250609-msm-dp-mst-v2-0-a54d8902a23d@quicinc.com> <20250609-msm-dp-mst-v2-1-a54d8902a23d@quicinc.com> <326bbd02-f414-48e3-a396-4b94f19054f7@quicinc.com> <014d535e-ca9c-4707-9ff4-7afdd489b780@quicinc.com> <521402f9-06c7-4d49-b78a-080b06378fd8@oss.qualcomm.com> <29900293-d297-4151-9bb1-2e7d9dd40a11@quicinc.com> Content-Language: en-US From: Dmitry Baryshkov In-Reply-To: <29900293-d297-4151-9bb1-2e7d9dd40a11@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODA2MDAwOCBTYWx0ZWRfX8P7S5y7/GV0d 2YhEXpgQ9jLvY1fnOiPHU0gF/EQS4p5Ckj37EhroU+0mFRCj7qlULkrfXER8TRq/0/BuajdWoUQ vagaWMtryw8SLk7q0sDAxUUBc/7aLEsOuIH+1wjzp1qv2aU+Tgb2K3hSw2SqM+W5NukMRo4Km2q vGatO6Oeo5p81TX/2XQ4vBqDdM1WwjBIz9M1Ys4aod84d1RPO5ZNh7k4yB9uTH5p8Luh2aWBAa+ H7Xf7mgH/0vbz/eta1lDAIGV8DTU4QRxhkyn/JZYEh5u/tWSoZ/XDoC1twSnbJoCAQoLdznBUnt X4bZ+3Bb4zhXHGJc6PAK4fy1dn/wsUQMWh5C0p8K6rSmgbx+XsGr4T+Quw4kxwKlO2KlTqlr828 Fcd1Bibp X-Authority-Analysis: v=2.4 cv=J8Cq7BnS c=1 sm=1 tr=0 ts=68933101 cx=c_pps a=mDZGXZTwRPZaeRUbqKGCBw==:117 a=j4ogTh8yFefVWWEFDRgCtg==:17 a=IkcTkHD0fZMA:10 a=2OwXVqhp2XgA:10 a=VwQbUJbxAAAA:8 a=COk6AnOGAAAA:8 a=oNfeFjo7KokIY7eomS0A:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=zc0IvFSfCIW2DFIPzwfm:22 a=TjNXssC_j7lpFel5tvFf:22 X-Proofpoint-GUID: lsoVYHrJnZVgD_-l163j_rviky864nfQ X-Proofpoint-ORIG-GUID: lsoVYHrJnZVgD_-l163j_rviky864nfQ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-08-06_02,2025-08-04_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 bulkscore=0 priorityscore=1501 adultscore=0 malwarescore=0 clxscore=1015 impostorscore=0 suspectscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2508060008 On 06/08/2025 14:33, Yongxing Mou wrote: > > > On 2025/6/27 20:40, Dmitry Baryshkov wrote: >> On 27/06/2025 10:49, Yongxing Mou wrote: >>> >>> >>> On 2025/6/25 21:32, Dmitry Baryshkov wrote: >>>> On Wed, Jun 25, 2025 at 04:43:55PM +0800, Yongxing Mou wrote: >>>>> >>>>> >>>>> On 2025/6/9 20:41, Dmitry Baryshkov wrote: >>>>>> On Mon, Jun 09, 2025 at 08:21:20PM +0800, Yongxing Mou wrote: >>>>>>> From: Abhinav Kumar >>>>>>> >>>>>>> In preparation of DP MST where link caps are read for the >>>>>>> immediate downstream device and the edid is read through >>>>>> >>>>>> EDID, not edid. Please review all your patches for up/down case. >>>>>> >>>>> Got it. Thanks~ >>>>>>> sideband messaging, split the msm_dp_panel_read_sink_caps() into >>>>>>> two parts which read the link parameters and the edid parts >>>>>>> respectively. Also drop the panel drm_edid cached as we actually >>>>>>> don't need it. >>>>>> >>>>>> Also => separate change. >>>>>> >>>>> Got it. >>>>>>> >>>>>>> Signed-off-by: Abhinav Kumar >>>>>>> Signed-off-by: Yongxing Mou >>>>>>> --- >>>>>>>    drivers/gpu/drm/msm/dp/dp_display.c | 13 +++++---- >>>>>>>    drivers/gpu/drm/msm/dp/dp_panel.c   | 55 +++++++++++++++++++ >>>>>>> +----------------- >>>>>>>    drivers/gpu/drm/msm/dp/dp_panel.h   |  6 ++-- >>>>>>>    3 files changed, 40 insertions(+), 34 deletions(-) >>>>>>> >>>>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/ >>>>>>> drm/ msm/dp/dp_display.c >>>>>>> index >>>>>>> 6f05a939ce9e648e9601597155999b6f85adfcff..4a9b65647cdef1ed6c3bb851f93df0db8be977af 100644 >>>>>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c >>>>>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c >>>>>>> @@ -389,7 +389,11 @@ static int >>>>>>> msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp) >>>>>>>        dp->link->lttpr_count = msm_dp_display_lttpr_init(dp, dpcd); >>>>>>> -    rc = msm_dp_panel_read_sink_caps(dp->panel, connector); >>>>>>> +    rc = msm_dp_panel_read_link_caps(dp->panel); >>>>>>> +    if (rc) >>>>>>> +        goto end; >>>>>>> + >>>>>>> +    rc = msm_dp_panel_read_edid(dp->panel, connector); >>>>>>>        if (rc) >>>>>>>            goto end; >>>>>>> @@ -720,7 +724,6 @@ static int msm_dp_irq_hpd_handle(struct >>>>>>> msm_dp_display_private *dp, u32 data) >>>>>>>    static void msm_dp_display_deinit_sub_modules(struct >>>>>>> msm_dp_display_private *dp) >>>>>>>    { >>>>>>>        msm_dp_audio_put(dp->audio); >>>>>>> -    msm_dp_panel_put(dp->panel); >>>>>>>        msm_dp_aux_put(dp->aux); >>>>>>>    } >>>>>>> @@ -783,7 +786,7 @@ static int msm_dp_init_sub_modules(struct >>>>>>> msm_dp_display_private *dp) >>>>>>>            rc = PTR_ERR(dp->ctrl); >>>>>>>            DRM_ERROR("failed to initialize ctrl, rc = %d\n", rc); >>>>>>>            dp->ctrl = NULL; >>>>>>> -        goto error_ctrl; >>>>>>> +        goto error_link; >>>>>>>        } >>>>>>>        dp->audio = msm_dp_audio_get(dp->msm_dp_display.pdev, dp- >>>>>>> >catalog); >>>>>>> @@ -791,13 +794,11 @@ static int msm_dp_init_sub_modules(struct >>>>>>> msm_dp_display_private *dp) >>>>>>>            rc = PTR_ERR(dp->audio); >>>>>>>            pr_err("failed to initialize audio, rc = %d\n", rc); >>>>>>>            dp->audio = NULL; >>>>>>> -        goto error_ctrl; >>>>>>> +        goto error_link; >>>>>>>        } >>>>>>>        return rc; >>>>>>> -error_ctrl: >>>>>>> -    msm_dp_panel_put(dp->panel); >>>>>>>    error_link: >>>>>>>        msm_dp_aux_put(dp->aux); >>>>>>>    error: >>>>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/ >>>>>>> msm/dp/dp_panel.c >>>>>>> index >>>>>>> 4e8ab75c771b1e3a2d62f75e9993e1062118482b..d9041e235104a74b3cc50ff2e307eae0c4301ef3 100644 >>>>>>> --- a/drivers/gpu/drm/msm/dp/dp_panel.c >>>>>>> +++ b/drivers/gpu/drm/msm/dp/dp_panel.c >>>>>>> @@ -118,14 +118,13 @@ static u32 >>>>>>> msm_dp_panel_get_supported_bpp(struct msm_dp_panel *msm_dp_panel, >>>>>>>        return min_supported_bpp; >>>>>>>    } >>>>>>> -int msm_dp_panel_read_sink_caps(struct msm_dp_panel *msm_dp_panel, >>>>>>> -    struct drm_connector *connector) >>>>>>> +int msm_dp_panel_read_link_caps(struct msm_dp_panel *msm_dp_panel) >>>>>>>    { >>>>>>>        int rc, bw_code; >>>>>>>        int count; >>>>>>>        struct msm_dp_panel_private *panel; >>>>>>> -    if (!msm_dp_panel || !connector) { >>>>>>> +    if (!msm_dp_panel) { >>>>>>>            DRM_ERROR("invalid input\n"); >>>>>>>            return -EINVAL; >>>>>>>        } >>>>>>> @@ -160,26 +159,29 @@ int msm_dp_panel_read_sink_caps(struct >>>>>>> msm_dp_panel *msm_dp_panel, >>>>>>>        rc = drm_dp_read_downstream_info(panel->aux, msm_dp_panel- >>>>>>> >dpcd, >>>>>>>                         msm_dp_panel->downstream_ports); >>>>>>> -    if (rc) >>>>>>> -        return rc; >>>>>>> +    return rc; >>>>>>> +} >>>>>>> -    drm_edid_free(msm_dp_panel->drm_edid); >>>>>>> +int msm_dp_panel_read_edid(struct msm_dp_panel *msm_dp_panel, >>>>>>> struct drm_connector *connector) >>>>>>> +{ >>>>>>> +    struct msm_dp_panel_private *panel; >>>>>>> +    const struct drm_edid *drm_edid; >>>>>>> + >>>>>>> +    panel = container_of(msm_dp_panel, struct >>>>>>> msm_dp_panel_private, msm_dp_panel); >>>>>>> -    msm_dp_panel->drm_edid = drm_edid_read_ddc(connector, >>>>>>> &panel- >aux->ddc); >>>>>>> +    drm_edid = drm_edid_read_ddc(connector, &panel->aux->ddc); >>>>>>> -    drm_edid_connector_update(connector, msm_dp_panel->drm_edid); >>>>>>> +    drm_edid_connector_update(connector, drm_edid); >>>>>>> -    if (!msm_dp_panel->drm_edid) { >>>>>>> +    if (!drm_edid) { >>>>>>>            DRM_ERROR("panel edid read failed\n"); >>>>>>>            /* check edid read fail is due to unplug */ >>>>>>>            if (!msm_dp_catalog_link_is_connected(panel->catalog)) { >>>>>>> -            rc = -ETIMEDOUT; >>>>>>> -            goto end; >>>>>>> +            return -ETIMEDOUT; >>>>>>>            } >>>>>>>        } >>>>>>> -end: >>>>>>> -    return rc; >>>>>>> +    return 0; >>>>>>>    } >>>>>>>    u32 msm_dp_panel_get_mode_bpp(struct msm_dp_panel *msm_dp_panel, >>>>>>> @@ -208,15 +210,20 @@ u32 msm_dp_panel_get_mode_bpp(struct >>>>>>> msm_dp_panel *msm_dp_panel, >>>>>>>    int msm_dp_panel_get_modes(struct msm_dp_panel *msm_dp_panel, >>>>>>>        struct drm_connector *connector) >>>>>>>    { >>>>>>> +    struct msm_dp_panel_private *panel; >>>>>>> +    const struct drm_edid *drm_edid; >>>>>>> + >>>>>>>        if (!msm_dp_panel) { >>>>>>>            DRM_ERROR("invalid input\n"); >>>>>>>            return -EINVAL; >>>>>>>        } >>>>>>> -    if (msm_dp_panel->drm_edid) >>>>>>> -        return drm_edid_connector_add_modes(connector); >>>>>>> +    panel = container_of(msm_dp_panel, struct >>>>>>> msm_dp_panel_private, msm_dp_panel); >>>>>>> + >>>>>>> +    drm_edid = drm_edid_read_ddc(connector, &panel->aux->ddc); >>>>>>> +    drm_edid_connector_update(connector, drm_edid); >>>>>> >>>>>> If EDID has been read and processed after HPD high event, why do >>>>>> we need >>>>>> to re-read it again? Are we expecting that EDID will change? >>>>>> >>>>> Here we indeed don't need to read the EDID again, so we can >>>>> directly call >>>>> drm_edid_connector_add_modes. Thanks. >>>>>>> -    return 0; >>>>>>> +    return drm_edid_connector_add_modes(connector); >>>>>>>    } >>>>>>>    static u8 msm_dp_panel_get_edid_checksum(const struct edid *edid) >>>>>>> @@ -229,6 +236,7 @@ static u8 >>>>>>> msm_dp_panel_get_edid_checksum(const struct edid *edid) >>>>>>>    void msm_dp_panel_handle_sink_request(struct msm_dp_panel >>>>>>> *msm_dp_panel) >>>>>>>    { >>>>>>>        struct msm_dp_panel_private *panel; >>>>>>> +    const struct drm_edid *drm_edid; >>>>>>>        if (!msm_dp_panel) { >>>>>>>            DRM_ERROR("invalid input\n"); >>>>>>> @@ -238,8 +246,13 @@ void msm_dp_panel_handle_sink_request(struct >>>>>>> msm_dp_panel *msm_dp_panel) >>>>>>>        panel = container_of(msm_dp_panel, struct >>>>>>> msm_dp_panel_private, msm_dp_panel); >>>>>>>        if (panel->link->sink_request & DP_TEST_LINK_EDID_READ) { >>>>>>> +        drm_edid = drm_edid_read_ddc(msm_dp_panel->connector, >>>>>>> &panel->aux->ddc); >>>>>> >>>>>> And again.... >>>>>> >>>>> Here we need the struct edid,since we drop the cached drm_edid, so >>>>> we need >>>>> to read it again. Or we can return the drm_edid from >>>>> msm_dp_panel_read_edid >>>>> and pass it to msm_dp_panel_handle_sink_request, then we don't need >>>>> to read >>>>> drm_edid here. Emm, I'm still a bit curious why we can't cache the >>>>> drm_edid? >>>>> It would help us to access it when needed. Emm, i see other drivers >>>>> also >>>>> cache it. >>>> >>>> Yes, they can cache EDID. However, in this case we don't even need >>>> it at >>>> all. This piece needs to be rewritten to use >>>> drm_dp_send_real_edid_checksum(), connector->real_edid_checksum. >>>> >>>> Corresponding changes can be submitted separately. >>>> >>> Got it, thanks, will separate this patch from MST patches..  Even if >>> we use drm_dp_send_real_edid_checksum to send connector- >>>  >real_edid_checksum, that’s only when the EDID state is incorrect. >>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ >>> tree/ drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c? >>> h=v6.16-rc3#n1020 >>>   When the EDID is read correctly, it should send edid->checksum >>> instead. >> >> I wonder if we should fix the drm_edid to always set >> real_edid_checksum instead. >> > Emm, can i understand that is another issue exist in the currently DRM.. Currently it's more of a design issue. -- With best wishes Dmitry