[Skiboot] [PATCH] FSP/CONSOLE: Disable notification on unresponsive consoles

Vasant Hegde hegdevasant at linux.vnet.ibm.com
Fri Oct 27 21:50:45 AEDT 2017


Commit fd6b71fc fixed the situation where ipmi console was open (hvc0) but got
data on different console (hvc1).

During FSP R/R OPAL closes all consoles. After R/R complete FSP requests to
open hvc1 and sends data on this. If hvc1 registration failed or not opened in
host kernel then it will not read data and results in RCU stalls.

Note that this is workaround for older kernel where we don't have separate irq
for each console. Latest kernel works fine without this patch.

CC: stable
CC: Sam Mendoza-Jonas <sam at mendozajonas.com>
Signed-off-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>
---
 hw/fsp/fsp-console.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/hw/fsp/fsp-console.c b/hw/fsp/fsp-console.c
index e3628d7..8d845d8 100644
--- a/hw/fsp/fsp-console.c
+++ b/hw/fsp/fsp-console.c
@@ -704,6 +704,7 @@ static int64_t fsp_console_read(int64_t term_number, int64_t *length,
 	struct fsp_serbuf_hdr *sb;
 	bool pending = false;
 	uint32_t old_nin, n, i, chunk, req = *length;
+	int rc = OPAL_SUCCESS;
 
 	if (term_number < 0 || term_number >= MAX_SERIAL)
 		return OPAL_PARAMETER;
@@ -712,8 +713,8 @@ static int64_t fsp_console_read(int64_t term_number, int64_t *length,
 		return OPAL_PARAMETER;
 	lock(&fsp_con_lock);
 	if (!fs->open) {
-		unlock(&fsp_con_lock);
-		return OPAL_CLOSED;
+		rc = OPAL_CLOSED;
+		goto clr_flag;
 	}
 	if (fs->waiting)
 		fs->waiting = 0;
@@ -744,6 +745,7 @@ static int64_t fsp_console_read(int64_t term_number, int64_t *length,
 	       buffer[4], buffer[5], buffer[6], buffer[7]);
 #endif /* OPAL_DEBUG_CONSOLE_IO */
 
+clr_flag:
 	/* Might clear the input pending flag */
 	for (i = 0; i < MAX_SERIAL && !pending; i++) {
 		struct fsp_serial *fs = &fsp_serials[i];
@@ -772,7 +774,7 @@ static int64_t fsp_console_read(int64_t term_number, int64_t *length,
 
 	unlock(&fsp_con_lock);
 
-	return OPAL_SUCCESS;
+	return rc;
 }
 
 void fsp_console_poll(void *data __unused)
-- 
2.9.3



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