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From: Daniel Vetter <daniel@ffwll.ch>
To: Carlos Palminha <CARLOS.PALMINHA@synopsys.com>
Cc: Linux Fbdev development list <linux-fbdev@vger.kernel.org>,
	Alexey Brodkin <Alexey.Brodkin@synopsys.com>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Tomi Valkeinen <tomi.valkeinen@ti.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Subject: Re: Whats missing in my new FB DRM driver... "No connectors reported connected with modes"?
Date: Fri, 22 Jan 2016 07:41:29 +0000	[thread overview]
Message-ID: <CAKMK7uFxPvZhAio59yqbQLv_JPBPeRkmF6bnknc3Gh1mA=9LiA@mail.gmail.com> (raw)
In-Reply-To: <56A11EF1.3070004@synopsys.com>

On Thu, Jan 21, 2016 at 7:09 PM, Carlos Palminha
<CARLOS.PALMINHA@synopsys.com> wrote:
> i made some progress in identifying the issue...
> When my driver calls drm_fb_helper_initial_config it seems DRM blocks waiting for register_framebuffer to return.
> The sequence is drm_fb_helper_initial_config->drm_fb_helper_single_fb_probe->register_framebuffer.
>
> Its strange because register_framebuffer function is just a mutex around do_register_framebuffer.
>
> Any clue?!

Ah, the curse of console_lock. drm_fb_helper_initial_config also does
the initial modeset if you have fbcon enabled. But because of locking
stupidity we must do _all_ that code (which means pretty much your
entire driver) under the console_lock, which means no log output until
console_unlock. Not even on serial port.

https://patchwork.freedesktop.org/patch/57951/ is the usual hack to
use to get rid of console_lock while booting, so that you can see
where your driver crashes. I guess we should explain this in the
kerneldoc ...
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

WARNING: multiple messages have this Message-ID (diff)
From: Daniel Vetter <daniel@ffwll.ch>
To: Carlos Palminha <CARLOS.PALMINHA@synopsys.com>
Cc: Linux Fbdev development list <linux-fbdev@vger.kernel.org>,
	Alexey Brodkin <Alexey.Brodkin@synopsys.com>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Tomi Valkeinen <tomi.valkeinen@ti.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Subject: Re: Whats missing in my new FB DRM driver... "No connectors reported connected with modes"?
Date: Fri, 22 Jan 2016 08:41:29 +0100	[thread overview]
Message-ID: <CAKMK7uFxPvZhAio59yqbQLv_JPBPeRkmF6bnknc3Gh1mA=9LiA@mail.gmail.com> (raw)
In-Reply-To: <56A11EF1.3070004@synopsys.com>

On Thu, Jan 21, 2016 at 7:09 PM, Carlos Palminha
<CARLOS.PALMINHA@synopsys.com> wrote:
> i made some progress in identifying the issue...
> When my driver calls drm_fb_helper_initial_config it seems DRM blocks waiting for register_framebuffer to return.
> The sequence is drm_fb_helper_initial_config->drm_fb_helper_single_fb_probe->register_framebuffer.
>
> Its strange because register_framebuffer function is just a mutex around do_register_framebuffer.
>
> Any clue?!

Ah, the curse of console_lock. drm_fb_helper_initial_config also does
the initial modeset if you have fbcon enabled. But because of locking
stupidity we must do _all_ that code (which means pretty much your
entire driver) under the console_lock, which means no log output until
console_unlock. Not even on serial port.

https://patchwork.freedesktop.org/patch/57951/ is the usual hack to
use to get rid of console_lock while booting, so that you can see
where your driver crashes. I guess we should explain this in the
kerneldoc ...
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/dri-devel

  parent reply	other threads:[~2016-01-22  7:41 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-30 18:46 Whats missing in my new FB DRM driver... "No connectors reported connected with modes"? Carlos Palminha
2015-12-30 18:53 ` Carlos Palminha
2015-12-30 18:53   ` Carlos Palminha
2015-12-31  2:19 ` Xinliang Liu
2016-01-18 14:32   ` Carlos Palminha
2016-01-18 14:32     ` Carlos Palminha
2016-01-18 14:45     ` Carlos Palminha
2016-01-18 14:45       ` Carlos Palminha
2016-01-19  3:38       ` Xinliang Liu
2016-01-19 16:03         ` Carlos Palminha
2016-01-19 16:03           ` Carlos Palminha
2016-01-19 16:52           ` Carlos Palminha
2016-01-19 16:52             ` Carlos Palminha
2016-01-20  1:24             ` Xinliang Liu
2016-01-20  1:24               ` Xinliang Liu
2016-01-21 18:09               ` Carlos Palminha
2016-01-21 18:09                 ` Carlos Palminha
2016-01-21 18:30                 ` Whats missing in my new FB DRM driver in ARC... waiting for console_lock to return Carlos Palminha
2016-01-21 18:30                   ` Carlos Palminha
2016-01-21 18:30                   ` Carlos Palminha
2016-01-22  8:32                   ` Daniel Stone
2016-01-22  8:32                     ` Daniel Stone
2016-01-22  8:32                     ` Daniel Stone
2016-01-28 14:20                   ` Alexey Brodkin
2016-01-28 14:20                     ` Alexey Brodkin
2016-01-28 14:20                     ` Alexey Brodkin
2016-01-28 15:42                     ` Rob Clark
2016-01-28 15:42                       ` Rob Clark
2016-01-28 15:42                       ` Rob Clark
2016-01-22  7:41                 ` Daniel Vetter [this message]
2016-01-22  7:41                   ` Whats missing in my new FB DRM driver... "No connectors reported connected with modes"? Daniel Vetter
2016-01-22  8:34                   ` Daniel Stone
2016-01-22  8:34                     ` Daniel Stone

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