<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED --- - [945gm regression] LVDS boots to blank screen" href="https://bugs.freedesktop.org/show_bug.cgi?id=53926#c43">Comment # 43</a> on <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED --- - [945gm regression] LVDS boots to blank screen" href="https://bugs.freedesktop.org/show_bug.cgi?id=53926">bug 53926</a> from <a class="email" href="mailto:nmschulte@gmail.com" title="Nathan Schulte <nmschulte@gmail.com>"> Nathan Schulte</a> <pre>Created <a href="attachment.cgi?id=72707" name="attach_72707" title="dmesg and intel_reg_* logs for various boots">attachment 72707</a> <a href="attachment.cgi?id=72707&action=edit" title="dmesg and intel_reg_* logs for various boots">[details]</a> dmesg and intel_reg_* logs for various boots I am experiencing this bug as well, on a fresh install of Debian Sid. I can control the backlight just fine, and it does indeed appear to be a race condition as there are [rare] times that I boot into a console with KMS without issues. I am experiencing it with both the kernel in Debian Sid as well as the 3.7 kernel from their experimental repo: $ uname -a # 3.2, unstable kernel Linux desmas-l 3.2.0-4-amd64 #1 SMP Debian 3.2.35-2 x86_64 GNU/Linux $ uname -a # 3.7, experimental kernel Linux desmas-l 3.7-trunk-amd64 #1 SMP Debian 3.7.1-1~experimental.2 x86_64 GNU/Linux I have found two workarounds to this: 1) Adding the i915 kernel module to my initramfs. 2) Booting with the kernel parameter video=SVIDEO-1:d I have attached the output from dmesg for booting with the 3.2 kernel, as well as the 3.7 kernel, all with the kernel parameter drm.debug=0xe, and for both with and without the video=SVIDEO-1:d workaround. In addition you will find intel_reg_dumper outputs, as well as intel_reg_reads for 0x70000 and 0x71000 for the 3.2 boots; I could not get the tools to work for the 3.7 kernel, failing with the following message: Couldn't map MMIO region: Resource temporarily unavailable Lastly, there is a dmesg from a 3.7 boot that worked without a workaround. Please let me know if there is anything else I can assist with! I will attempt a git bisect as I am familiar with that process. I can provide i915.modeset=0 or nomodeset boot dmesg logs as well if needed. -- Nate</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>