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From: "Alexander E. Patrakov" <patrakov@gmail.com>
To: "David Herrmann"
	<dh.herrmann-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"Ville Syrjälä"
	<ville.syrjala-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: Linux Fbdev development list
	<linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Jingoo Han <jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	"xorg-devel-go0+a7rfsptAfugRpC6u6w@public.gmane.org"
	<xorg-devel-go0+a7rfsptAfugRpC6u6w@public.gmane.org>,
	dri-devel
	<dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>,
	Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Dave Airlie <airlied-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: Fixing the kernels backlight API
Date: Thu, 13 Feb 2014 06:37:51 +0000	[thread overview]
Message-ID: <52FC683F.10905@gmail.com> (raw)
In-Reply-To: <CANq1E4R=UVo5YVPUrdRFeobAE-qU6e-+GHZ2VJwwaa8zEO6g3Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

13.02.2014 04:26, David Herrmann wrote:
> The "attach" stuff actually sounds doable, but who decides which one
> to attach? You still need some user-space script during device-plug
> for that.
> But to be honest, the simplest way would be a "backlightd"
> bus-activatable daemon. SetBacklight() then takes a DRM-connector and
> brightness-value, which the daemon looks up in /sys and sets.. This
> has the advantage that we can do any fancy matching in user-space. We
> can provide quirks (maybe even via udev-hwdb) and other helpers for
> weird setups.

What would be done with Samsung monitors (like an old SyncMaster 770P) 
that have a DVI connection, no physical buttons and have to be 
controlled via DDC-CI? Currently, ddccontrol works (via /dev/i2c-*), but 
only from root. I would like this use case to be covered in such a way 
that it could work both in Xorg and in Wayland, and, if possible, 
without races related to i2c usage from the kernel and from userspace.

-- 
Alexander E. Patrakov

WARNING: multiple messages have this Message-ID (diff)
From: "Alexander E. Patrakov" <patrakov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: "David Herrmann"
	<dh.herrmann-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"Ville Syrjälä"
	<ville.syrjala-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: Linux Fbdev development list
	<linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Jingoo Han <jg1.han-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	"xorg-devel-go0+a7rfsptAfugRpC6u6w@public.gmane.org"
	<xorg-devel-go0+a7rfsptAfugRpC6u6w@public.gmane.org>,
	dri-devel
	<dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>,
	Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Dave Airlie <airlied-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: Fixing the kernels backlight API
Date: Thu, 13 Feb 2014 12:37:51 +0600	[thread overview]
Message-ID: <52FC683F.10905@gmail.com> (raw)
In-Reply-To: <CANq1E4R=UVo5YVPUrdRFeobAE-qU6e-+GHZ2VJwwaa8zEO6g3Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

13.02.2014 04:26, David Herrmann wrote:
> The "attach" stuff actually sounds doable, but who decides which one
> to attach? You still need some user-space script during device-plug
> for that.
> But to be honest, the simplest way would be a "backlightd"
> bus-activatable daemon. SetBacklight() then takes a DRM-connector and
> brightness-value, which the daemon looks up in /sys and sets.. This
> has the advantage that we can do any fancy matching in user-space. We
> can provide quirks (maybe even via udev-hwdb) and other helpers for
> weird setups.

What would be done with Samsung monitors (like an old SyncMaster 770P) 
that have a DVI connection, no physical buttons and have to be 
controlled via DDC-CI? Currently, ddccontrol works (via /dev/i2c-*), but 
only from root. I would like this use case to be covered in such a way 
that it could work both in Xorg and in Wayland, and, if possible, 
without races related to i2c usage from the kernel and from userspace.

-- 
Alexander E. Patrakov
_______________________________________________
xorg-devel-go0+a7rfsptAfugRpC6u6w@public.gmane.org: X.Org development
Archives: http://lists.x.org/archives/xorg-devel
Info: http://lists.x.org/mailman/listinfo/xorg-devel

  parent reply	other threads:[~2014-02-13  6:37 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-12 15:12 Fixing the kernels backlight API Hans de Goede
2014-02-12 15:12 ` Hans de Goede
     [not found] ` <52FB8F45.9060006-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-02-12 20:14   ` Dave Airlie
2014-02-12 20:14     ` Dave Airlie
     [not found]     ` <CAPM=9tyYLuoTtW69-cPx-JSuar++D5WEtYRZr_-aP7uowZpVyA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-02-12 20:43       ` Ville Syrjälä
2014-02-12 20:43         ` Ville Syrjälä
2014-02-12 22:26         ` David Herrmann
2014-02-12 22:26           ` David Herrmann
     [not found]           ` <CANq1E4R=UVo5YVPUrdRFeobAE-qU6e-+GHZ2VJwwaa8zEO6g3Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-02-13  6:37             ` Alexander E. Patrakov [this message]
2014-02-13  6:37               ` Alexander E. Patrakov
     [not found]               ` <52FC683F.10905-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-02-13 13:57                 ` Hans de Goede
2014-02-13 13:57                   ` Hans de Goede
2014-02-13 13:49             ` Hans de Goede
2014-02-13 13:49               ` Hans de Goede
2014-02-13 13:41       ` Hans de Goede
2014-02-13 13:41         ` Hans de Goede
2014-02-13 17:19         ` Matthew Garrett
     [not found]           ` <20140213171932.GB4420-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org>
2014-02-13 19:43             ` Hans de Goede
2014-02-13 19:43               ` Hans de Goede
     [not found]               ` <52FD204E.40507-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-02-13 20:12                 ` Matthew Garrett
2014-02-13 20:12                   ` Matthew Garrett
     [not found]                   ` <20140213201237.GA19355-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org>
2014-02-14  8:45                     ` Hans de Goede
2014-02-14  8:45                       ` Hans de Goede

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