[34-longterm 050/247] rapidio: fix hang on RapidIO doorbell queue full condition

Paul Gortmaker
2011-06-23T17:30:55Z

From: Thomas Taranowski <tom@baringforge.com>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------

commit 12a4dc43911785f51a596f771ae0701b18d436f1 upstream.

In fsl_rio_dbell_handler() the code currently simply acknowledges the QFI
queue full interrupt, but does nothing to resolve the queue full
condition. Instead, it jumps to the end of the isr. When a queue full
condition occurs, the isr is then re-entered immediately and continually,
forever.

The fix is to just fall through and read out current doorbell entries.

Signed-off-by: Thomas Taranowski <tom@baringforge.com>
Cc: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Micha Nelissen <micha@neli.hopto.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
arch/powerpc/sysdev/fsl_rio.c | 1 -
1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/sysdev/fsl_rio.c b/arch/powerpc/sysdev/fsl_rio.c
index 71fba88..2aa6c93 100644
--- a/arch/powerpc/sysdev/fsl_rio.c
+++ b/arch/powerpc/sysdev/fsl_rio.c
@@ -833,7 +833,6 @@ fsl_rio_dbell_handler(int irq, void *dev_instance)
if (dsr & DOORBELL_DSR_QFI) {
pr_info("RIO: doorbell queue full\n");
out_be32(&priv->msg_regs->dsr, DOORBELL_DSR_QFI);
- goto out;
}

/* XXX Need to check/dispatch until queue empty */
--
1.7.4.4