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<p>Hello all,</p>
<p><br>
</p>
<p>when I updated my Kernel from version 5.4.155 to 5.4.215 I get an
strange xhci error:</p>
<p><i>xhci-hcd f10f0000.usb3: ERROR unknown event type 37</i><i><br>
</i><i>xhci-hcd f10f0000.usb3: ERROR Transfer event TRB DMA ptr
not part of current TD ep_index 2 comp_code 13</i><i><br>
</i></p>
<p>After a lot of this messages, my hardware makes a reboot without
any more outputs.</p>
<p>The error only occures when i add <i>console=null</i> to my
kernel bootargs. When I add instead console=<i>ttyS0,115200</i> no
error occured.</p>
<p>Now I go back in kernelversions. The error occured first in
version 5.4.159. Between patchlevel 158 and 159 there is a change:</p>
<p><i>--- linux-5.4.158/kernel/printk/printk.c 2021-11-06
13:59:45.000000000 +0100</i><i><br>
</i><i>+++ linux-5.4.159/kernel/printk/printk.c 2021-11-12
14:43:05.000000000 +0100</i><i><br>
</i><i>@@ -2193,8 +2193,15 @@</i><i><br>
</i><i> char *s, *options, *brl_options = NULL;</i><i><br>
</i><i> int idx;</i><i><br>
</i><i> </i><i><br>
</i><i>- if (str[0] == 0)</i><i><br>
</i><i>+ /*</i><i><br>
</i><i>+ * console="" or console=null have been suggested as a
way to</i><i><br>
</i><i>+ * disable console output. Use ttynull that has been
created</i><i><br>
</i><i>+ * for exacly this purpose.</i><i><br>
</i><i>+ */</i><i><br>
</i><i>+ if (str[0] == 0 || strcmp(str, "null") == 0) {</i><i><br>
</i><i>+ __add_preferred_console("ttynull", 0, NULL, NULL);</i><i><br>
</i><i> return 1;</i><i><br>
</i><i>+ }</i><i><br>
</i><i> </i><i><br>
</i><i> if (_braille_console_setup(&str,
&brl_options))</i><i><br>
</i><i> return 1;</i></p>
<p>I checked my kernelconfig and found that I have no ttynull device
configured (<i>CONFIG_NULL_TTY=n</i>). Add <i>CONFIG_NULL_TTY=y</i>
to my kernelconfig doesn't made a change.</p>
<p>When I undo the change above, everything works fine.</p>
<p><br>
</p>
<p>Does anybody know, what could be the main trigger for the error
above?<br>
</p>
<p><br>
</p>
<p>Regards,</p>
<p>Sarah<br>
</p>
<p><br>
</p>
<p><br>
</p>
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