On Thu, 26 Jun 2014, "Wang, Quanxian" <quanxian.w...@intel.com> wrote: >> -----Original Message----- >> From: Jani Nikula [mailto:jani.nik...@linux.intel.com] >> Sent: Tuesday, June 24, 2014 11:58 PM >> To: Wang, Quanxian >> Cc: intel-gfx@lists.freedesktop.org; Daniel Vetter >> Subject: RE: [Intel-gfx] [PATCH] drm/i915/vlv: DP_SINK_COUNT is not reliable >> for valleyview platform. >> >> >> Per DP spec we need to read the SINK_COUNT. Perhaps your problem is >> >> the hotplug irqs? >> > [Wang, Quanxian] Hi, Jani >> > The log event is about the transaction event instead of hotplug event. It >> > is >> general since they will use I2c to read byte one by one. It will generate >> many >> transaction. >> > >> > But the root cause is really about hotplug(intel_hpd_irq_handler). When >> we switch to console, there will be a hotplug event happens after a while. >> After that, the system will continually get the hotplug event to switch sink >> device on and off periodly. With DisplayPort 1.2 spec, '' This bit is used >> for >> either monitor hotplug/unplug or for notification of a sink event.", I am not >> sure if it is notification of a sink event or real hotplug event. We have no >> code to identify the difference between hotplug/unplug and notification of >> a sink event. I check display port spec and also not found how to identify >> them differently. >> > >> > Question is: >> > In function intel_dp_detect_dpcd, before checking SINK_COUNT, we will >> use intel_dp_get_dpcd to get the dpcd. Could we think there is an active sink >> device attached to branch device if dpcd content is not null. >> > According to the display port spec, only sink device has dpcd, if we get >> > one, >> there must be a sink device attached to branch device or source device. >> Right? >> >> No. From your logs, the DPCD has bit 0 set in address 5h, which means >> downstream port present, which is only allowed in branch devices. > [Wang, Quanxian] Ok. Currently I have some founds. > > Sink device attached to branch device will be idle without operation after a > while. And kernel will > get the 'fake dpms off' event and called intel_encoder_dpms to disable the > connector and dp link will be disabled(See the 1st line of log list below, > intel_encoder_dpms will be called with DPMS off). At that time, kernel > thought connector had no any sink device attached when SINK_COUNT return 0. > Status will be changed from connected to disconnected. Encoder will be > deleted after that. Whatever for console terminal or other apps which depends > on connector will not work. In this case, The system is in black status even > if you press any key or others. From ssh terminal, we could find kernel gets > hpd event continually, however at that time, encoder is deleted, connector is > not be restored. Always get '[CRTC:6] [NOFB ]'. > > So SINK_COUNT is not the only way to check the alive status for connector. If > we got one or more, we can confirm that connector is alive. However if we get > 0, we should not say connector is not alive. We should try another way to > make sure if it is alive. > > I have tried with DDC checking if SINK_COUNT is 0. It works for DP > with branch device. But if disconnect the sink device from Branch > device, it will not work.
Huh, if you disconnect the sink device from branch device, SINK_COUNT is expected to be 0, and the result is expected to be disconnected, right?! BR, Jani. > So I *plan*: > 1) when we get SINK_COUNT to be 0, don't return disconnected. We will > continue to check DDC. > 2) or firstly check OUI to make sure if there is branch device, if there is, > then check DDC if SINK_COUNT is 0. > > Any suggestion for this process? > > [ 1334.170715] [drm:intel_encoder_dpms], mode:3 > [ 1334.170721] [drm:intel_crtc_update_dpms], > [ 1334.170726] [drm:i9xx_crtc_disable], > [ 1334.170730] [drm:intel_disable_dp], > [ 1334.170735] [drm:intel_dp_aux_native_write], > [ 1334.170741] [drm:intel_dp_aux_native_write], retry 0 > [ 1334.201477] [drm:intel_post_disable_dp], > [ 1334.201483] [drm:intel_dp_link_down], > [ 1334.253549] [drm:g4x_wait_for_vblank], vblank wait timed out > [ 1334.256743] [drm:valleyview_update_wm], Setting FIFO watermarks - A: > plane=2, cursor=2, B: plane=2, cursor=2, SR: plane=0, cursor=0 > [ 1334.256761] [drm:check_encoder_state], [ENCODER:10:DAC-10] > [ 1334.256769] [drm:check_encoder_state], [ENCODER:11:TMDS-11] > [ 1334.256777] [drm:check_encoder_state], [ENCODER:15:TMDS-15] > [ 1334.256784] [drm:check_crtc_state], [CRTC:3] > [ 1334.256791] [drm:check_crtc_state], [CRTC:6] > [ 1340.097288] [drm:valleyview_irq_handler], hotplug event happens 0x20020000 > & 0x007e08c0??? > [ 1340.097311] [drm:intel_hpd_irq_handler], Received HPD interrupt on PIN 4 - > cnt: 0 > [ 1340.097417] [drm:i915_hotplug_work_func], running encoder hotplug functions > [ 1340.097436] [drm:i915_hotplug_work_func], Connector HDMI-A-1 (pin 4) > received hotplug event. > [ 1340.097450] [drm:i915_hotplug_work_func], Connector DP-1 (pin 4) received > hotplug event. > [ 1340.097464] [drm:intel_hdmi_detect], [CONNECTOR:12:HDMI-A-1] > [ 1340.104895] [drm:drm_do_probe_ddc_edid], drm: skipping non-existent > adapter i915 gmbus dpb > [ 1340.104913] [drm:intel_dp_detect], [CONNECTOR:16:DP-1] > [ 1340.104925] [drm:intel_dp_detect_dpcd], Get dpcd > [ 1340.105757] [drm:intel_dp_aux_native_read], aux_ch read and got 15 bytes > [ 1340.105772] [drm:intel_dp_aux_native_read_retry], expected 15, and get 15 > [ 1340.105785] [drm:intel_dp_get_dpcd], DPCD: 11 0a 82 01 01 15 01 81 00 01 > 04 01 0f 00 00 > [ 1340.106330] [drm:intel_dp_aux_native_read], aux_ch read and got 16 bytes > [ 1340.106345] [drm:intel_dp_aux_native_read_retry], expected 16, and get 16 > [ 1340.106355] [drm:intel_dp_detect_dpcd], Check dpcd > [ 1340.106365] [drm:intel_dp_detect_dpcd], get aux_native reg > [ 1340.106772] [drm:intel_dp_aux_native_read], aux_ch read and got 1 bytes > [ 1340.106786] [drm:intel_dp_aux_native_read_retry], expected 1, and get 1 > [ 1340.106798] [drm:intel_dp_detect_dpcd], Check SINK_COUNT reg:0x0, 0 > [ 1340.106814] [drm:intel_hpd_irq_event], [CONNECTOR:16:DP-1] status updated > from connected to disconnected > [ 1340.108038] [drm:drm_fb_helper_hotplug_event], > > > -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx
