* [PATCH] drm: count reaches -1, tested 0
@ 2009-02-08 14:25 Roel Kluin
2009-02-09 2:28 ` Dave Airlie
2009-02-09 22:22 ` Thomas Hellström
0 siblings, 2 replies; 4+ messages in thread
From: Roel Kluin @ 2009-02-08 14:25 UTC (permalink / raw)
To: airlied; +Cc: dri-devel, lkml
With a postfix decrement count will reach -1 rather than 0,
subsequent tests fail.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/drivers/gpu/drm/via/via_dma.c b/drivers/gpu/drm/via/via_dma.c
index 7a339db..600315c 100644
--- a/drivers/gpu/drm/via/via_dma.c
+++ b/drivers/gpu/drm/via/via_dma.c
@@ -481,9 +481,9 @@ static int via_wait_idle(drm_via_private_t * dev_priv)
{
int count = 10000000;
- while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && count--);
+ while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && --count);
- while (count-- && (VIA_READ(VIA_REG_STATUS) &
+ while (--count && (VIA_READ(VIA_REG_STATUS) &
(VIA_CMD_RGTR_BUSY | VIA_2D_ENG_BUSY |
VIA_3D_ENG_BUSY))) ;
return count;
@@ -705,7 +705,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
switch (d_siz->func) {
case VIA_CMDBUF_SPACE:
while (((tmp_size = via_cmdbuf_space(dev_priv)) < d_siz->size)
- && count--) {
+ && --count) {
if (!d_siz->wait) {
break;
}
@@ -717,7 +717,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
break;
case VIA_CMDBUF_LAG:
while (((tmp_size = via_cmdbuf_lag(dev_priv)) > d_siz->size)
- && count--) {
+ && --count) {
if (!d_siz->wait) {
break;
}
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] drm: count reaches -1, tested 0
2009-02-08 14:25 [PATCH] drm: count reaches -1, tested 0 Roel Kluin
@ 2009-02-09 2:28 ` Dave Airlie
2009-02-09 22:22 ` Thomas Hellström
1 sibling, 0 replies; 4+ messages in thread
From: Dave Airlie @ 2009-02-09 2:28 UTC (permalink / raw)
To: Roel Kluin; +Cc: airlied, dri-devel, lkml, Thomas Hellström
On Mon, Feb 9, 2009 at 12:25 AM, Roel Kluin <roel.kluin@gmail.com> wrote:
> With a postfix decrement count will reach -1 rather than 0,
> subsequent tests fail.
Thomas can you sign off on this?
Dave.
>
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
> diff --git a/drivers/gpu/drm/via/via_dma.c b/drivers/gpu/drm/via/via_dma.c
> index 7a339db..600315c 100644
> --- a/drivers/gpu/drm/via/via_dma.c
> +++ b/drivers/gpu/drm/via/via_dma.c
> @@ -481,9 +481,9 @@ static int via_wait_idle(drm_via_private_t * dev_priv)
> {
> int count = 10000000;
>
> - while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && count--);
> + while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && --count);
>
> - while (count-- && (VIA_READ(VIA_REG_STATUS) &
> + while (--count && (VIA_READ(VIA_REG_STATUS) &
> (VIA_CMD_RGTR_BUSY | VIA_2D_ENG_BUSY |
> VIA_3D_ENG_BUSY))) ;
> return count;
> @@ -705,7 +705,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
> switch (d_siz->func) {
> case VIA_CMDBUF_SPACE:
> while (((tmp_size = via_cmdbuf_space(dev_priv)) < d_siz->size)
> - && count--) {
> + && --count) {
> if (!d_siz->wait) {
> break;
> }
> @@ -717,7 +717,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
> break;
> case VIA_CMDBUF_LAG:
> while (((tmp_size = via_cmdbuf_lag(dev_priv)) > d_siz->size)
> - && count--) {
> + && --count) {
> if (!d_siz->wait) {
> break;
> }
>
> --
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] drm: count reaches -1, tested 0
2009-02-08 14:25 [PATCH] drm: count reaches -1, tested 0 Roel Kluin
2009-02-09 2:28 ` Dave Airlie
@ 2009-02-09 22:22 ` Thomas Hellström
2009-02-10 20:48 ` [PATCH v2] " Roel Kluin
1 sibling, 1 reply; 4+ messages in thread
From: Thomas Hellström @ 2009-02-09 22:22 UTC (permalink / raw)
To: Roel Kluin; +Cc: airlied, dri-devel, lkml
Hi!
Roel Kluin wrote:
> With a postfix decrement count will reach -1 rather than 0,
> subsequent tests fail.
>
This code is about to be abandoned, but if we're going to fix it,
instead of pushing the problem to then next while loop, what about
while (count && condition)
count--;
Can you redo the patch based on that?
Thanks,
Thomas
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
> diff --git a/drivers/gpu/drm/via/via_dma.c b/drivers/gpu/drm/via/via_dma.c
> index 7a339db..600315c 100644
> --- a/drivers/gpu/drm/via/via_dma.c
> +++ b/drivers/gpu/drm/via/via_dma.c
> @@ -481,9 +481,9 @@ static int via_wait_idle(drm_via_private_t * dev_priv)
> {
> int count = 10000000;
>
> - while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && count--);
> + while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && --count);
>
> - while (count-- && (VIA_READ(VIA_REG_STATUS) &
> + while (--count && (VIA_READ(VIA_REG_STATUS) &
> (VIA_CMD_RGTR_BUSY | VIA_2D_ENG_BUSY |
> VIA_3D_ENG_BUSY))) ;
> return count;
> @@ -705,7 +705,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
> switch (d_siz->func) {
> case VIA_CMDBUF_SPACE:
> while (((tmp_size = via_cmdbuf_space(dev_priv)) < d_siz->size)
> - && count--) {
> + && --count) {
> if (!d_siz->wait) {
> break;
> }
> @@ -717,7 +717,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
> break;
> case VIA_CMDBUF_LAG:
> while (((tmp_size = via_cmdbuf_lag(dev_priv)) > d_siz->size)
> - && count--) {
> + && --count) {
> if (!d_siz->wait) {
> break;
> }
>
>
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^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v2] drm: count reaches -1, tested 0
2009-02-09 22:22 ` Thomas Hellström
@ 2009-02-10 20:48 ` Roel Kluin
0 siblings, 0 replies; 4+ messages in thread
From: Roel Kluin @ 2009-02-10 20:48 UTC (permalink / raw)
To: Thomas Hellström; +Cc: airlied, dri-devel, lkml
Thomas Hellström wrote:
> This code is about to be abandoned, but if we're going to fix it,
> instead of pushing the problem to then next while loop, what about
>
> while (count && condition)
> count--;
>
> Can you redo the patch based on that?
Very well reviewed, thanks. Like this?
------------------->8-----------------------8<------------------------
With a postfix decrement in the test count will reach -1 rather than 0,
subsequent tests fail.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/drivers/gpu/drm/via/via_dma.c b/drivers/gpu/drm/via/via_dma.c
index 7a339db..029c22a 100644
--- a/drivers/gpu/drm/via/via_dma.c
+++ b/drivers/gpu/drm/via/via_dma.c
@@ -481,11 +481,12 @@ static int via_wait_idle(drm_via_private_t * dev_priv)
{
int count = 10000000;
- while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && count--);
+ while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && --count)
+ ;
- while (count-- && (VIA_READ(VIA_REG_STATUS) &
- (VIA_CMD_RGTR_BUSY | VIA_2D_ENG_BUSY |
- VIA_3D_ENG_BUSY))) ;
+ while (count && (VIA_READ(VIA_REG_STATUS) & (VIA_CMD_RGTR_BUSY |
+ VIA_2D_ENG_BUSY | VIA_3D_ENG_BUSY)))
+ count--;
return count;
}
@@ -705,7 +706,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
switch (d_siz->func) {
case VIA_CMDBUF_SPACE:
while (((tmp_size = via_cmdbuf_space(dev_priv)) < d_siz->size)
- && count--) {
+ && --count) {
if (!d_siz->wait) {
break;
}
@@ -717,7 +718,7 @@ static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *
break;
case VIA_CMDBUF_LAG:
while (((tmp_size = via_cmdbuf_lag(dev_priv)) > d_siz->size)
- && count--) {
+ && --count) {
if (!d_siz->wait) {
break;
}
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-02-10 20:53 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2009-02-08 14:25 [PATCH] drm: count reaches -1, tested 0 Roel Kluin
2009-02-09 2:28 ` Dave Airlie
2009-02-09 22:22 ` Thomas Hellström
2009-02-10 20:48 ` [PATCH v2] " Roel Kluin
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