From: Nathan Lynch <nathanl@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: jirislaby@kernel.org, linux-kernel@vger.kernel.org,
gregkh@linuxfoundation.org
Subject: [PATCH] powerpc/udbg_hvc: retry putc on -EAGAIN
Date: Fri, 14 May 2021 16:44:22 -0500 [thread overview]
Message-ID: <20210514214422.3019105-1-nathanl@linux.ibm.com> (raw)
hvterm_raw_put_chars() calls hvc_put_chars(), which may return -EAGAIN
when the underlying hcall returns a "busy" status, but udbg_hvc_putc()
doesn't handle this. When using xmon on a PowerVM guest, this can
result in incomplete or garbled output when printing relatively large
amounts of data quickly, such as when dumping the kernel log buffer.
Call again on -EAGAIN.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
drivers/tty/hvc/hvc_vio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/hvc/hvc_vio.c b/drivers/tty/hvc/hvc_vio.c
index 798f27f40cc2..76d2a7038095 100644
--- a/drivers/tty/hvc/hvc_vio.c
+++ b/drivers/tty/hvc/hvc_vio.c
@@ -249,7 +249,7 @@ static void udbg_hvc_putc(char c)
count = hvterm_hvsi_put_chars(0, &c, 1);
break;
}
- } while(count == 0);
+ } while(count == 0 || count == -EAGAIN);
}
static int udbg_hvc_getc_poll(void)
--
2.30.2
next reply other threads:[~2021-05-14 21:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-14 21:44 Nathan Lynch [this message]
2021-05-21 12:47 ` [PATCH] powerpc/udbg_hvc: retry putc on -EAGAIN Greg KH
2021-05-23 10:51 ` Michael Ellerman
2021-05-27 11:10 ` Greg KH
2021-06-06 12:08 ` Michael Ellerman
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