2009-01-01 11:09:23

by Yauhen Kharuzhy

[permalink] [raw]
Subject: [PATCH] s3cmci: Fix hangup in do_pio_write()

This commit fixes the regression what was added by commit
088a78af978d0c8e339071a9b2bca1f4cb368f30 "s3cmci: Support transfers
which are not multiple of 32 bits."

fifo_free() now returns amount of available space in FIFO buffer in
bytes. But do_pio_write() writes to FIFO 32-bit words. Condition for
return from cycle is (fifo_free() == 0), but when fifo has 1..3 bytes of
free space then this condition will never be true and system hangs.

This patch changes condition in the while() to (fifo_free() > 3).

Signed-off-by: Yauhen Kharuzhy <[email protected]>
---
drivers/mmc/host/s3cmci.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/s3cmci.c b/drivers/mmc/host/s3cmci.c
index fd6b5b8..9778deb 100644
--- a/drivers/mmc/host/s3cmci.c
+++ b/drivers/mmc/host/s3cmci.c
@@ -329,7 +329,7 @@ static void do_pio_write(struct s3cmci_host *host)

to_ptr = host->base + host->sdidata;

- while ((fifo = fifo_free(host))) {
+ while ((fifo = fifo_free(host)) > 3) {
if (!host->pio_bytes) {
res = get_data_buffer(host, &host->pio_bytes,
&host->pio_ptr);
--
1.5.6.5


2009-01-12 14:44:19

by Pierre Ossman

[permalink] [raw]
Subject: Re: [PATCH] s3cmci: Fix hangup in do_pio_write()

On Thu, 1 Jan 2009 13:09:04 +0200
Yauhen Kharuzhy <[email protected]> wrote:

> This commit fixes the regression what was added by commit
> 088a78af978d0c8e339071a9b2bca1f4cb368f30 "s3cmci: Support transfers
> which are not multiple of 32 bits."
>
> fifo_free() now returns amount of available space in FIFO buffer in
> bytes. But do_pio_write() writes to FIFO 32-bit words. Condition for
> return from cycle is (fifo_free() == 0), but when fifo has 1..3 bytes of
> free space then this condition will never be true and system hangs.
>
> This patch changes condition in the while() to (fifo_free() > 3).
>
> Signed-off-by: Yauhen Kharuzhy <[email protected]>

Any objections here Ben? An Acked-by would be nice.

Rgds
--
-- Pierre Ossman

Linux kernel, MMC maintainer http://www.kernel.org
rdesktop, core developer http://www.rdesktop.org

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