From f53671c054ba0b5d5b10e2a7294786fa2f73479e Mon Sep 17 00:00:00 2001 From: Aurelien Jarno Date: Thu, 27 Jan 2011 08:21:35 +0100 Subject: [PATCH] escc: fix interrupt flags Recent PowerPC kernel end up in kernel panic during boot in -nographic mode. In this mode the second serial port is used as the udbg console, and thus a few characters are sent on this port. This activates the tx interrupt flag, and later choke the Linux kernel, as it was not expecting such a flag to be set. The problem here comes from the fact that contrary to most devices the interrupt flags are only set if the interrupt is enabled. Quoting the datasheet: "If the corresponding IE bit is not set, the IP for that source of interrupt will never be set." This patch fixes that by enabling the interrupt flag only when the corresponding interrupt is enabled. Cc: Blue Swirl Signed-off-by: Aurelien Jarno --- hw/escc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/hw/escc.c b/hw/escc.c index ba6063608d..f6fd9192ea 100644 --- a/hw/escc.c +++ b/hw/escc.c @@ -369,14 +369,18 @@ static inline void set_txint(ChannelState *s) if (!s->rxint_under_svc) { s->txint_under_svc = 1; if (s->chn == chn_a) { - s->rregs[R_INTR] |= INTR_TXINTA; + if (s->wregs[W_INTR] & INTR_TXINT) { + s->rregs[R_INTR] |= INTR_TXINTA; + } if (s->wregs[W_MINTR] & MINTR_STATUSHI) s->otherchn->rregs[R_IVEC] = IVEC_HITXINTA; else s->otherchn->rregs[R_IVEC] = IVEC_LOTXINTA; } else { s->rregs[R_IVEC] = IVEC_TXINTB; - s->otherchn->rregs[R_INTR] |= INTR_TXINTB; + if (s->wregs[W_INTR] & INTR_TXINT) { + s->otherchn->rregs[R_INTR] |= INTR_TXINTB; + } } escc_update_irq(s); } -- 2.34.1