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<base href="https://bugs.freedesktop.org/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - PROBLEM: Intel VGA output busticated on 4.3-rc2 (regression)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=92174">92174</a>
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<th>Summary</th>
<td>PROBLEM: Intel VGA output busticated on 4.3-rc2 (regression)
</td>
</tr>
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<th>Product</th>
<td>DRI
</td>
</tr>
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<th>Version</th>
<td>XOrg git
</td>
</tr>
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<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>major
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>DRM/Intel
</td>
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<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jairo.daniel.miramontes.caton@intel.com
</td>
</tr>
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<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr></table>
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<pre>On Thu, Sep 24, 2015 at 05:22:09PM -0400, Nick Bowler wrote:
<span class="quote">> Hi,
>
> Testing out 4.3-rc2, first thing I notice is that the VGA output is
> not working. Specifically, the display is continuously powering on
> and off -- at no point is any image visible on the screen (I am
> expecting to see the console output). The display connected to the
> HDMI output is working fine.
>
> Linux 4.2 did not suffer from this problem.
>
> In dmesg I see the following messages, which I do not see on a working
> kernel. Full dmesg from 4.3-rc2 is attached (gzipped).
>
> [ 0.115339] [drm:drm_calc_timestamping_constants] *ERROR* crtc
> 21: Can't calculate constants, dotclock = 0!
> [ 0.117582] [drm:intel_opregion_init] *ERROR* No ACPI video bus found
>
> This is an older machine with Intel G45 graphics.
>
> Unfortunately bisection is proving difficult, because the commits it
> wants me to test have a different problem: neither display comes up at
> all (both remain in standby). Partial results follow.
>
> Thanks,
> Nick
>
> git bisect start 'drivers/gpu/drm/i915'
> # bad: [1f93e4a96c9109378204c147b3eec0d0e8100fde] Linux 4.3-rc2
> git bisect bad 1f93e4a96c9109378204c147b3eec0d0e8100fde
> # good: [64291f7db5bd8150a74ad2036f1037e6a0428df2] Linux 4.2
> git bisect good 64291f7db5bd8150a74ad2036f1037e6a0428df2
> # skip: [a7a6c498927ea42c9a3b26e0caa5c854a980d58c] drm/i915:
> POSTING_READ() in intel_set_memory_cxsr()
> git bisect skip a7a6c498927ea42c9a3b26e0caa5c854a980d58c
> # skip: [031b698a77a70a6c394568034437b5486a44e868] drm/i915:
> Unconditionally do fb tracking invalidate in set_domain
> git bisect skip 031b698a77a70a6c394568034437b5486a44e868
> # skip: [adeca76d8e2b34b5c739a36f4191aed63080da40] drm/i915:
> Simplify i915_gem_execbuffer_retire_commands() parameters
> git bisect skip adeca76d8e2b34b5c739a36f4191aed63080da40
> # good: [369712e89404089fa559235bb1ee8fc40d976e6b] drm/i915: reduce
> duplicate conditions in i9xx_hpd_irq_handler
> git bisect good 369712e89404089fa559235bb1ee8fc40d976e6b
> # skip: [6eb1a6817246f1a67de4d6959a84d09efead5329] drm/i915: Read wm
> values from hardware at init on CHV
> git bisect skip 6eb1a6817246f1a67de4d6959a84d09efead5329
> # bad: [d14e7b6d1d8747826cb900db852351c550e00fdd] drm/i915: Check DP
> link status on long hpd too
> git bisect bad d14e7b6d1d8747826cb900db852351c550e00fdd
> # skip: [fe36f55d4d4447679923fc74564786ae423ca4bd] drm/i915/gtt:
> Cleanup page directory encoding
> git bisect skip fe36f55d4d4447679923fc74564786ae423ca4bd</span ></pre>
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