On Fri, Mar 9, 2012 at 5:28 PM, Yufeng Shen <miletus at chromium.org> wrote: > On Fri, Mar 9, 2012 at 3:15 AM, Maarten Maathuis <madman2003 at gmail.com> > wrote: >> On Fri, Mar 9, 2012 at 2:50 AM, Yufeng Shen <miletus at chromium.org> wrote: >>> So a simple case of ?disabling a CRTC and then re-enabling it. >>> >>> Disabling: >>> >>> CRTC X is originally connected to output Y >>> >>> 1. XRRSetCrtcConfig() ? ?is called to disable CRTC ?X >>> >>> 2. drm_helper_connector_dpms() ? then gets called on the connector >>> connected to CRTC X, >>> ? ?in the function, >>> ? ?the ?connector->encoder ?is set to DPMS OFF, ? and the >>> encoder->crtc ?set to DPMS OFF >>> ? ?but the ?encoder->crtc ? is still CRTC X >>> >>> Re-enabling: >>> >>> 3. XRRSetCrtcConfig() ? ?is called to to enable CRTC ?X ?on output Y >>> >>> 4. drm_crtc_helper_set_config () ?is now called, >>> suppose ? fb is not changed, ?mode is not changed, encoder is not changed >>> and the ? encoder->crtc ?is not changed, >>> then we have ? mode_changed == false ? ?and ?the mode is not reset >>> >>> So the CRTC X won't be connected to output Y. >>> >>> What I don't understand the code is that why ?XRRSetCrtcConfig() ?ends >>> up only calling ?drm_helper_connector_dpms() ?? >>> I think it should do more than that, at least it should set the >>> related ?encoder->crtc = NULL >>> >>> any comments ? >>> _______________________________________________ >>> dri-devel mailing list >>> dri-devel at lists.freedesktop.org >>> http://lists.freedesktop.org/mailman/listinfo/dri-devel >> >> As far as i know DPMS designed is a simple switch, meaning that the >> mode remains active, so if you do DPMS ON it should come back. If for >> some reason the driver is disconnecting the encoder from the crtc, >> then it is the drivers responsibility to reconnect it when DPMS ON >> happens. >> >> But don't take my word for it, others may have more/other information. >> > > Yes, I was thinking ideally DPMS call should enable/disable DPMS state, and > XRRSetCrtcConfig call should enable/disable CRTC. > > But it seems that, when using XRRSetCrtcConfig to disable CRTC, > the CRTC itself is disabled, the DPMS is disabled (DPMS OFF), > and then when using XRRSetCrtcConfig to re-enable the CRTC, > it only checks whether the CRTC that connected to the encoder is > changed (whether a new crtc is assigned), but does not check whether > the CRTC itself is previously disabled or not. ?So it considers the encoder > is connected to the same CRTC and does no thing to re-enable the CRTC. > > >> -- >> Far away from the primal instinct, the song seems to fade away, the >> river get wider between your thoughts and the things we do and say.
What i meant is that you should get a DPMS ON call somewhere in the driver. The driver should then re-enable things. If the driver disconnects the encoder for DPMS OFF, then it will also have to reconnect it for DPMS ON. -- Far away from the primal instinct, the song seems to fade away, the river get wider between your thoughts and the things we do and say.
