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authorTimur Tabi <timur@codeaurora.org>2017-07-28 00:15:52 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-07-30 17:53:44 +0300
commit37ef38f3f83891a2f413fb872bae7d0f9bb95b27 (patch)
tree30ac978fba7c794ca827f8a657bda94c7f28eaaf /include/linux/acpi.h
parent520eccdfe187591a51ea9ab4c1a024ae4d0f68d9 (diff)
downloadlinux-37ef38f3f83891a2f413fb872bae7d0f9bb95b27.tar.xz
tty: pl011: fix initialization order of QDF2400 E44
The work-around for Qualcomm Technologies QDF2400 Erratum 44 hinges on a global variable defined in the pl011 driver. The ACPI SPCR parsing code determines whether the work-around is needed, and if so, it changes the console name from "pl011" to "qdf2400_e44". The expectation is that the pl011 driver will implement the work-around when it sees the console name. The global variable qdf2400_e44_present is set when that happens. The problem is that work-around needs to be enabled when the pl011 driver probes, not when the console name is queried. However, sbsa_probe() is called before pl011_console_match(). The work-around appeared to work previously because the default console on QDF2400 platforms was always ttyAMA1. The first time sbsa_probe() is called (for ttyAMA0), qdf2400_e44_present is still false. Then pl011_console_match() is called, and it sets qdf2400_e44_present to true. All subsequent calls to sbsa_probe() enable the work-around. The solution is to move the global variable into spcr.c and let the pl011 driver query it during probe time. This works because all QDF2400 platforms require SPCR, so parse_spcr() will always be called. pl011_console_match still checks for the "qdf2400_e44" console name, but it doesn't do anything else special. Fixes: 5a0722b898f8 ("tty: pl011: use "qdf2400_e44" as the earlycon name for QDF2400 E44") Tested-by: Jeffrey Hugo <jhugo@codeaurora.org> Signed-off-by: Timur Tabi <timur@codeaurora.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/acpi.h')
-rw-r--r--include/linux/acpi.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index c749eef1daa1..27b4b6615263 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1209,6 +1209,7 @@ static inline bool acpi_has_watchdog(void) { return false; }
#endif
#ifdef CONFIG_ACPI_SPCR_TABLE
+extern bool qdf2400_e44_present;
int parse_spcr(bool earlycon);
#else
static inline int parse_spcr(bool earlycon) { return 0; }