From: Melchior FRANZ <melchior.franz@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Greg KH <greg@kroah.com>, dri-devel@lists.freedesktop.org
Subject: Re: i915 completely unusable in 2.6.38.x
Date: Tue, 26 Apr 2011 20:04:42 +0200 [thread overview]
Message-ID: <201104262004.42776@rk-nord.at> (raw)
In-Reply-To: <201104260959.53084@rk-nord.at>
* Melchior FRANZ -- Tuesday 26 April 2011:
> [https://bugzilla.kernel.org/show_bug.cgi?id=31522]
I've replied to this error message, but here again for this audience:
The commit that broke all 2.6.38.* releases for my machine is this:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=ba3820ade317ee36e496b9b40d2ec3987dd4aef0
(Takashi Iwai: "drm/i915: Revive combination mode for backlight
control").
In 'is_backlight_combination_mode()' INTEL_INFO(dev)->gen
equals 4, and the function returns 0x40000000 in "combination mode".
In 'intel_panel_get_backlight()' this happens:
val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK; // val = 0x0b4a
if (IS_PINEVIEW(dev)) // false
val >>= 1;
if (is_backlight_combination_mode(dev)){
u8 lbpc;
val &= ~1; // val = 0x0b4a
pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc); // lbpc = 0
val *= lbpc; // val = 0
}
The backlight remains off and does also not react to the "brighter" key
event.
Reverting the patch fixes my system, obviously.
m.
prev parent reply other threads:[~2011-04-26 18:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-25 9:14 i915 completely unusable in 2.6.38.x Boris B. Zhmurov
2011-04-25 9:15 ` Boris B. Zhmurov
2011-04-25 20:10 ` Melchior FRANZ
2011-04-25 21:03 ` Greg KH
2011-04-26 7:59 ` Melchior FRANZ
2011-04-26 10:31 ` Boris B. Zhmurov
2011-04-26 18:04 ` Melchior FRANZ [this message]
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