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Re: [Qemu-devel] hw/esp.c mishandles commands without dma
From: |
Martin Husemann |
Subject: |
Re: [Qemu-devel] hw/esp.c mishandles commands without dma |
Date: |
Sun, 17 Jun 2012 23:57:29 +0200 |
User-agent: |
Mutt/1.4.2.3i |
On Sun, Jun 17, 2012 at 11:55:20PM +0200, Martin Husemann wrote:
> The NetBSD driver sometimes uses commands without DMA (for example a simple
> TEST_UNIT_READY). On esp hardware, the command has a DMA bit (if dma is to
> be used), and when writing to the command register, the s->dma status is
> updated accordingly.
>
> When commands with dma are used and dma is disabled, the command is defered
> untill dma is enabled again. This is all fine. However, the deferal should
> not happen if the command does not use dma.
>
> This can bee seen by booting NetBSD/sparc: for every scsi device attached
> there will be a 5 second timeout and an error message.
>
> Here is a trivial patch wich fixes this problem for me:
>
> --- hw/esp.c.orig 2012-06-01 11:13:13.000000000 +0200
> +++ hw/esp.c 2012-06-18 01:43:34.000000000 +0200
> @@ -270,7 +270,7 @@ static void handle_satn(ESPState *s)
> uint8_t buf[32];
> int len;
>
> - if (!s->dma_enabled) {
> + if (s->dma && !s->dma_enabled) {
> s->dma_cb = handle_satn;
> return;
> }
> @@ -284,7 +284,7 @@ static void handle_s_without_atn(ESPStat
> uint8_t buf[32];
> int len;
>
> - if (!s->dma_enabled) {
> + if (s->dma && !s->dma_enabled) {
> s->dma_cb = handle_s_without_atn;
> return;
> }
> @@ -296,7 +296,7 @@ static void handle_s_without_atn(ESPStat
>
> static void handle_satn_stop(ESPState *s)
> {
> - if (!s->dma_enabled) {
> + if (s->dma && !s->dma_enabled) {
> s->dma_cb = handle_satn_stop;
> return;
> }
>
>
> I filed a ticket in the bugtracker for it: #1014099.
>
>
> Martin
Forgot to add:
Signed-off-by: Martin Husemann <address@hidden>