mode issue about no EDID and first mode when weston start

[Wang, Quanxian]

Ok, if we don't use builtin mode in weston. That is fine. In this case, I supposed to provide some useful error output to user instead of core dump weston.

Another case is if we don't get active mode from current connector, and at the same time EDID mode information from KMS is available. In this case, I use the first mode we get from KMS as the default mode for connector. If not, we will still core dump weston.

> -----Original Message-----
> From: Kristian Høgsberg [mailto:hoegsberg at gmail.com]
> Sent: Tuesday, July 31, 2012 5:15 AM
> To: Wang, Quanxian
> Cc: wayland-devel at lists.freedesktop.org
> Subject: Re: mode issue about no EDID and first mode when weston start
> 
> On Thu, Jul 26, 2012 at 07:54:45PM +0000, Wang, Quanxian wrote:
> > Hi, All
> >
> > Help review.
> >
> > Background
> >
> > 1) Some platforms has no EDID mode information. Therefore when KMS
> > initializes the driver, there will be no mode provided for user. At
> > that time, have to use the fixed mode defined by the
> > user.(builtin-800x480)
> 
> What you want to do in this case is to either compile an EDID blob into the
> kernel or specify one through the firmware mechanism.  See
> Documentation/EDID/HOWTO.txt in the kernel and use
> 
>   video=HDMI-A-1:e drm_kms_helper.edid_firmware=HDMI-A-1:edid
> 
> on the kernel command line.  This example assumes you're trying to bring up
> the HDMI-A-1 connector with an edid blob in /lib/firmware/edid.  That will
> bring up KMS early on and weston will be able to reuse the mode set from the
> custom EDID blob.  We will also add a feature to specify a modeline in
> weston.ini, so you'll be able to use that instead.  Something like:
> 
> [output]
> name=HDMI-A-1
> modeline=29.50  800 824 896 992  480 483 493 500 -hsync +vsync
> 
> I don't want to build in a mode in weston.  KMS should give us a valid mode in
> all cases and if it doesn't it's probably something like this case where you have
> a custom board/driver/panel.
> 
> Kristian
> 
> > 2) In the very beginning of weston restart, there exists a case, no
> > active mode is set to connector. We provide the first mode gotten from
> > KMS as default mode for connector.
> >
> > We got weston core dump when weston start because drm will add null
> > mode when cases above happen.
> >
> > commit 1a87302f288497ed8bbef3677286e27bb6931f72
> > Author: Wang Quanxian
> <quanxian.wang at intel.com<mailto:quanxian.wang at intel.com>>
> > Date:   Wed Jul 25 11:21:00 2012 +0800
> >
> >     Bug fix for mode issue when weston start
> >
> >     Provide the default builtin(800x480) mode when platforms
> >     have no EDID and KMS could not provide mode information.
> >     In the very beginning of weston, the connector could not
> >     be set active mode. At that time, take the first mode in
> >     mode list from KMS as default mode.
> >
> >     Signed-Off-By Quanxian Wang
> > <quanxian.wang at intel.com<mailto:quanxian.wang at intel.com>>
> >
> > diff --git a/src/compositor-drm.c b/src/compositor-drm.c index
> > 4dffa1d..47cd512 100644
> > --- a/src/compositor-drm.c
> > +++ b/src/compositor-drm.c
> > @@ -143,6 +143,16 @@ struct drm_sprite {
> >         uint32_t formats[];
> >  };
> >
> > +static drmModeModeInfo builtin_800x480 = {
> > +       33750,                  /* clock */
> > +       800, 864, 976, 1088, 0,
> > +       480, 486, 494, 517, 0,
> > +       59920,
> > +       DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC,
> > +       0,
> > +       "800x480"
> > +};
> > +
> >  static int
> >  surface_is_primary(struct weston_compositor *ec, struct
> > weston_surface *es)  { @@ -1344,13 +1354,30 @@
> > create_output_for_connector(struct drm_compositor *ec,
> >         drmModeFreeEncoder(encoder);
> >         if (crtc == NULL)
> >                 goto err_free;
> > -       crtc_mode = crtc->mode;
> > +
> > +       /* if don't get mode from drm driver, use default 800x480 */
> > +       if (crtc->mode.clock != 0)
> > +       {
> > +               crtc_mode = crtc->mode;
> > +       } else {
> > +               if (connector->count_modes == 0)
> > +                       crtc_mode = builtin_800x480;
> > +               else
> > +                       crtc_mode = connector->modes[0];
> > +       }
> > +
> >         drmModeFreeCrtc(crtc);
> >
> > -       for (i = 0; i < connector->count_modes; i++) {
> > -               ret = drm_output_add_mode(output,
> &connector->modes[i]);
> > +       if (connector->count_modes == 0) {
> > +               ret = drm_output_add_mode(output, &crtc_mode);
> >                 if (ret)
> >                         goto err_free;
> > +       }else{
> > +               for (i = 0; i < connector->count_modes; i++) {
> > +                       ret = drm_output_add_mode(output,
> &connector->modes[i]);
> > +                       if (ret)
> > +                               goto err_free;
> > +               }
> >         }
> >
> >         preferred = NULL;
> >
> >
> > Thanks
> >
> > Quanxian Wang
> >
> >
> 
> 
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