<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Linux 4.3 on Broadwell with i915.enable_fdc=0: "Unclaimed register detected after writing to register 0x4510c"" href="https://bugs.freedesktop.org/show_bug.cgi?id=92841#c1">Comment # 1</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Linux 4.3 on Broadwell with i915.enable_fdc=0: "Unclaimed register detected after writing to register 0x4510c"" href="https://bugs.freedesktop.org/show_bug.cgi?id=92841">bug 92841</a> from <a class="email" href="mailto:adam_richter2004@yahoo.com" title="Adam J. Richter <adam_richter2004@yahoo.com>"> Adam J. Richter</a> <pre>I don't know how I missed this: $ egrep -i 4510c drivers/gpu/drm/i915/*.h drivers/gpu/drm/i915/i915_reg.h:#define WM2_LP_ILK 0x4510c The only .c file containing the string WM2_LP_ILK is drivers/gpu/drm/i915/intel_pm.c, and the term "watermark" appears close to those uses, so I guess that is what "WM" stands for. It looks like this register is written unconditionally in ilk_init_lp_watermarks, and I am just guessing from the function name that it gets executed at initialization, so maybe there is something wrong with the other debugging code that I added. I expect I'll look into this tomorrow, but wanted to post this update now to avoid prompting anyone else do this bit of research that I should have done before posting. I apologize for not including this information in my initial bug report.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>