<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Dual-Core CPU E5500 / G45: RetroArch with reicast core results in corrupted graphics" href="https://bugs.freedesktop.org/show_bug.cgi?id=107212#c36">Comment # 36</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Dual-Core CPU E5500 / G45: RetroArch with reicast core results in corrupted graphics" href="https://bugs.freedesktop.org/show_bug.cgi?id=107212">bug 107212</a> from <a class="email" href="mailto:diego.viola@gmail.com" title="Diego Viola <diego.viola@gmail.com>"> Diego Viola</a> <pre>[diego@dualcore mesa]$ git bisect bad 8aee87fe4cce0a883867df3546db0e0a36908086 is the first bad commit commit 8aee87fe4cce0a883867df3546db0e0a36908086 Author: Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>> Date: Fri Feb 20 14:09:17 2015 -0800 i965: Use SIMD16 instead of SIMD8 on Gen4 when possible. Gen5+ systems allow you to specify multiple shader programs - both SIMD8 and SIMD16 - and the hardware will automatically dispatch to the most appropriate one, given the number of subspans to be processed. However, that is not the case on Gen4. Instead, you program a single shader. If you enable multiple dispatch modes (SIMD8 and SIMD16), the shader is supposed to contain a series of jump instructions at the beginning. The hardware will launch the shader at a small offset, hitting one of the jumps. We've always thought that sounds like a pain, and weren't clear how it affected performance - is it worth having multiple shader types? So, we never bothered with SIMD16 until now. This patch takes a simpler approach: try and compile a SIMD16 shader. If possible, set the no_8 flag, telling the hardware to just use the SIMD16 variant all the time. Signed-off-by: Kenneth Graunke <<a href="mailto:kenneth@whitecape.org">kenneth@whitecape.org</a>> Reviewed-by: Jordan Justen <<a href="mailto:jordan.l.justen@intel.com">jordan.l.justen@intel.com</a>> :040000 040000 a0bac15a1f0b79b629c912cdcee2265f8a968d81 45a6b6fb2fd15aab6b877277ecee33b41cad2ef4 M src [diego@dualcore mesa]$</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are on the CC list for the bug.</li> </ul> </body> </html>