<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_REOPENED " title="REOPENED --- - [snb] vsync hang" href="https://bugs.freedesktop.org/show_bug.cgi?id=68718#c25">Comment # 25</a> on <a class="bz_bug_link bz_status_REOPENED " title="REOPENED --- - [snb] vsync hang" href="https://bugs.freedesktop.org/show_bug.cgi?id=68718">bug 68718</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>(In reply to <a href="show_bug.cgi?id=68718#c24">comment #24</a>) > Lastly, it looks like there's a PIPEA_SLC (0x70004) which I guess needs to > be programmed on [DevSNB:D2], whatever that is (I'm hoping "pre-release hw"). Right, (SLC = scanline counter) which is programmed by setting DE_LOAD_SL. The tricky part is that DE_LOAD_SL only exists for later chips - some early production chips do not have the register and so have no way to program PIPE*_SLC. In fact, can you do intel_reg_read 0x4f100? Or intel_reg_write 0x4f100 0xdeadbeef; intel_reg_read 0x4f100 > No idea if these apply, and you were probably already aware of these things, > but thought I'd mention anyways. (Is MI_SUSPEND_FLUSH used? Can the commands > get broken up into different batch buffers behind the scenes? What's CB^2?) No, those restrictions do not apply as we neither use suspend flush, non-secure batch buffer for LRI, ppgtt batches or chained batchbuffers (CB^2). > Lastly, is the masking logic for DERRMR correct? It uses ~event... I > couldn't find the spec for what the various bits actually mean, I guess > they're meant to line up with the MI_WAIT_FOR_EVENT bits? It is just a happy coincidence on SNB that the bits do line up between DERRMR and the WAIT_FOR_EVENT. Yes, I have checked those many times. > Would be good to > double-check... (Also, why do you need to store the DERRMR value somewhere? > Seems odd to me, but what do I know.) Because the hardware is broken, and this is one of the w/a. I don't think it is required because the wait will ensure that the flush will happen before we write to the same register again, hence why I left it out of the original code. But it was something easy enough to test. Again.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>