From d2266bbfa9e3e32e3b642965088ca461bd24a94f Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Wed, 3 Oct 2018 00:49:21 +0800 Subject: x86/earlyprintk: Add a force option for pciserial device The "pciserial" earlyprintk variant helps much on many modern x86 platforms, but unfortunately there are still some platforms with PCI UART devices which have the wrong PCI class code. In that case, the current class code check does not allow for them to be used for logging. Add a sub-option "force" which overrides the class code check and thus the use of such device can be enforced. [ bp: massage formulations. ] Suggested-by: Borislav Petkov Signed-off-by: Feng Tang Signed-off-by: Borislav Petkov Cc: "H. Peter Anvin" Cc: "Stuart R . Anderson" Cc: Bjorn Helgaas Cc: David Rientjes Cc: Feng Tang Cc: Frederic Weisbecker Cc: Greg Kroah-Hartman Cc: H Peter Anvin Cc: Ingo Molnar Cc: Jiri Kosina Cc: Jonathan Corbet Cc: Kai-Heng Feng Cc: Kate Stewart Cc: Konrad Rzeszutek Wilk Cc: Peter Zijlstra Cc: Philippe Ombredanne Cc: Thomas Gleixner Cc: Thymo van Beers Cc: alan@linux.intel.com Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/20181002164921.25833-1-feng.tang@intel.com --- Documentation/admin-guide/kernel-parameters.txt | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 92eb1f42240d..34e6800dea0e 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1063,7 +1063,7 @@ earlyprintk=serial[,0x...[,baudrate]] earlyprintk=ttySn[,baudrate] earlyprintk=dbgp[debugController#] - earlyprintk=pciserial,bus:device.function[,baudrate] + earlyprintk=pciserial[,force],bus:device.function[,baudrate] earlyprintk=xdbc[xhciController#] earlyprintk is useful when the kernel crashes before @@ -1095,6 +1095,10 @@ The sclp output can only be used on s390. + The optional "force" to "pciserial" enables use of a + PCI device even when its classcode is not of the + UART class. + edac_report= [HW,EDAC] Control how to report EDAC event Format: {"on" | "off" | "force"} on: enable EDAC to report H/W event. May be overridden -- cgit v1.2.3