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[AMD Official Use Only - General]<br>
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<p class="MsoNormal"><span style="mso-fareast-language:ZH-CN">Loop Charlie.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:ZH-CN"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:ZH-CN">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:ZH-CN">Rico</span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Sent from <a href="https://go.microsoft.com/fwlink/?LinkId=550986">
Mail</a> for Windows</p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="border:none;padding:0in"><b>From: </b><a href="mailto:tianci.yin@amd.com">Tianci Yin</a><br>
<b>Sent: </b>Monday, February 6, 2023 3:59 PM<br>
<b>To: </b><a href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a><br>
<b>Cc: </b><a href="mailto:Harry.Wentland@amd.com">Wentland, Harry</a>; <a href="mailto:Rodrigo.Siqueira@amd.com">
Siqueira, Rodrigo</a>; <a href="mailto:Aurabindo.Pillai@amd.com">Pillai, Aurabindo</a>;
<a href="mailto:Tianci.Yin@amd.com">Yin, Tianci (Rico)</a><br>
<b>Subject: </b>[PATCH] drm/amd/display: Disable migration to ensure consistency of per-CPU variable</p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">From: tiancyin <tianci.yin@amd.com><br>
<br>
[why]<br>
Since the variable fpu_recursion_depth is per-CPU type, it has one copy<br>
on each CPU, thread migration causes data consistency issue, then the<br>
call trace shows up. And preemption disabling can't prevent migration.<br>
<br>
[how]<br>
Disable migration to ensure consistency of fpu_recursion_depth.<br>
<br>
Signed-off-by: tiancyin <tianci.yin@amd.com><br>
---<br>
amdgpu_dm/dc_fpu.c | 2 ++<br>
1 file changed, 2 insertions(+)<br>
<br>
diff --git a/amdgpu_dm/dc_fpu.c b/amdgpu_dm/dc_fpu.c<br>
index 1743ca0a36..c42aa947c9 100644<br>
--- a/amdgpu_dm/dc_fpu.c<br>
+++ b/amdgpu_dm/dc_fpu.c<br>
@@ -89,6 +89,7 @@ void dc_fpu_begin(const char *function_name, const int line)<br>
<br>
if (*pcpu == 1) {<br>
#if defined(CONFIG_X86)<br>
+ migrate_disable();<br>
kernel_fpu_begin();<br>
#elif defined(CONFIG_PPC64)<br>
if (cpu_has_feature(CPU_FTR_VSX_COMP)) {<br>
@@ -129,6 +130,7 @@ void dc_fpu_end(const char *function_name, const int line)<br>
if (*pcpu <= 0) {<br>
#if defined(CONFIG_X86)<br>
kernel_fpu_end();<br>
+ migrate_enable();<br>
#elif defined(CONFIG_PPC64)<br>
if (cpu_has_feature(CPU_FTR_VSX_COMP)) {<br>
disable_kernel_vsx();<br>
-- <br>
2.34.1<o:p></o:p></p>
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