* [PATCH] drm/tinydrm: mipi-dbi: Fix unbalanced DMA access
@ 2017-08-01 20:14 ` David Lechner
0 siblings, 0 replies; 7+ messages in thread
From: David Lechner @ 2017-08-01 20:14 UTC (permalink / raw)
To: dri-devel; +Cc: David Lechner, Noralf Trønnes, David Airlie, linux-kernel
If we return here and import_attach is true, then dma_buf_end_cpu_access()
will not be called balance dma_buf_begin_cpu_access().
Fix by setting ret instead of returning.
Signed-off-by: David Lechner <david@lechnology.com>
---
drivers/gpu/drm/tinydrm/mipi-dbi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
index c83eeb7..e10fa4b 100644
--- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
+++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
@@ -183,7 +183,8 @@ static int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
drm_get_format_name(fb->format->format,
&format_name));
- return -EINVAL;
+ ret = -EINVAL;
+ break;
}
if (import_attach)
--
2.7.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH] drm/tinydrm: mipi-dbi: Fix unbalanced DMA access
@ 2017-08-01 20:14 ` David Lechner
0 siblings, 0 replies; 7+ messages in thread
From: David Lechner @ 2017-08-01 20:14 UTC (permalink / raw)
To: dri-devel; +Cc: David Lechner, linux-kernel
If we return here and import_attach is true, then dma_buf_end_cpu_access()
will not be called balance dma_buf_begin_cpu_access().
Fix by setting ret instead of returning.
Signed-off-by: David Lechner <david@lechnology.com>
---
drivers/gpu/drm/tinydrm/mipi-dbi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
index c83eeb7..e10fa4b 100644
--- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
+++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
@@ -183,7 +183,8 @@ static int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
drm_get_format_name(fb->format->format,
&format_name));
- return -EINVAL;
+ ret = -EINVAL;
+ break;
}
if (import_attach)
--
2.7.4
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/tinydrm: mipi-dbi: Fix unbalanced DMA access
2017-08-01 20:14 ` David Lechner
@ 2017-08-02 18:51 ` Noralf Trønnes
-1 siblings, 0 replies; 7+ messages in thread
From: Noralf Trønnes @ 2017-08-02 18:51 UTC (permalink / raw)
To: David Lechner, dri-devel; +Cc: David Airlie, linux-kernel
Den 01.08.2017 22.14, skrev David Lechner:
> If we return here and import_attach is true, then dma_buf_end_cpu_access()
> will not be called balance dma_buf_begin_cpu_access().
>
> Fix by setting ret instead of returning.
>
> Signed-off-by: David Lechner <david@lechnology.com>
> ---
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
> drivers/gpu/drm/tinydrm/mipi-dbi.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
> index c83eeb7..e10fa4b 100644
> --- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
> +++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
> @@ -183,7 +183,8 @@ static int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
> dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
> drm_get_format_name(fb->format->format,
> &format_name));
> - return -EINVAL;
> + ret = -EINVAL;
> + break;
> }
>
> if (import_attach)
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/tinydrm: mipi-dbi: Fix unbalanced DMA access
@ 2017-08-02 18:51 ` Noralf Trønnes
0 siblings, 0 replies; 7+ messages in thread
From: Noralf Trønnes @ 2017-08-02 18:51 UTC (permalink / raw)
To: David Lechner, dri-devel; +Cc: linux-kernel
Den 01.08.2017 22.14, skrev David Lechner:
> If we return here and import_attach is true, then dma_buf_end_cpu_access()
> will not be called balance dma_buf_begin_cpu_access().
>
> Fix by setting ret instead of returning.
>
> Signed-off-by: David Lechner <david@lechnology.com>
> ---
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
> drivers/gpu/drm/tinydrm/mipi-dbi.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
> index c83eeb7..e10fa4b 100644
> --- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
> +++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
> @@ -183,7 +183,8 @@ static int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
> dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
> drm_get_format_name(fb->format->format,
> &format_name));
> - return -EINVAL;
> + ret = -EINVAL;
> + break;
> }
>
> if (import_attach)
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/tinydrm: mipi-dbi: Fix unbalanced DMA access
2017-08-01 20:14 ` David Lechner
(?)
(?)
@ 2017-08-03 22:41 ` David Lechner
2017-08-04 6:49 ` Noralf Trønnes
-1 siblings, 1 reply; 7+ messages in thread
From: David Lechner @ 2017-08-03 22:41 UTC (permalink / raw)
To: dri-devel; +Cc: Noralf Trønnes, David Airlie, linux-kernel
On 08/01/2017 03:14 PM, David Lechner wrote:
> If we return here and import_attach is true, then dma_buf_end_cpu_access()
> will not be called balance dma_buf_begin_cpu_access().
>
> Fix by setting ret instead of returning.
>
> Signed-off-by: David Lechner <david@lechnology.com>
> ---
> drivers/gpu/drm/tinydrm/mipi-dbi.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
> index c83eeb7..e10fa4b 100644
> --- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
> +++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
> @@ -183,7 +183,8 @@ static int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
> dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
> drm_get_format_name(fb->format->format,
> &format_name));
> - return -EINVAL;
> + ret = -EINVAL;
> + break;
> }
>
> if (import_attach)
>
I just realized that the next line here can mask ret.
if (import_attach)
ret = dma_buf_end_cpu_access(import_attach->dmabuf,
DMA_FROM_DEVICE);
So, we should either ignore the return value from
dma_buf_end_cpu_access() always or add some logic to ignore it if ret is
already an error.
In some of the other patches I have been sending, we have the same
situation. I those, I have opted to just ignore the return value from
dma_buf_end_cpu_access(). e.g...
if (import_attach)
dma_buf_end_cpu_access(import_attach->dmabuf, DMA_FROM_DEVICE);
Is this a reasonable thing to do?
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/tinydrm: mipi-dbi: Fix unbalanced DMA access
2017-08-03 22:41 ` David Lechner
@ 2017-08-04 6:49 ` Noralf Trønnes
2017-08-07 18:00 ` David Lechner
0 siblings, 1 reply; 7+ messages in thread
From: Noralf Trønnes @ 2017-08-04 6:49 UTC (permalink / raw)
To: David Lechner, dri-devel; +Cc: David Airlie, linux-kernel
Den 04.08.2017 00.41, skrev David Lechner:
> On 08/01/2017 03:14 PM, David Lechner wrote:
>> If we return here and import_attach is true, then
>> dma_buf_end_cpu_access()
>> will not be called balance dma_buf_begin_cpu_access().
>>
>> Fix by setting ret instead of returning.
>>
>> Signed-off-by: David Lechner <david@lechnology.com>
>> ---
>> drivers/gpu/drm/tinydrm/mipi-dbi.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c
>> b/drivers/gpu/drm/tinydrm/mipi-dbi.c
>> index c83eeb7..e10fa4b 100644
>> --- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
>> +++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
>> @@ -183,7 +183,8 @@ static int mipi_dbi_buf_copy(void *dst, struct
>> drm_framebuffer *fb,
>> dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
>> drm_get_format_name(fb->format->format,
>> &format_name));
>> - return -EINVAL;
>> + ret = -EINVAL;
>> + break;
>> }
>> if (import_attach)
>>
>
>
> I just realized that the next line here can mask ret.
>
>
> if (import_attach)
> ret = dma_buf_end_cpu_access(import_attach->dmabuf,
> DMA_FROM_DEVICE);
>
> So, we should either ignore the return value from
> dma_buf_end_cpu_access() always or add some logic to ignore it if ret
> is already an error.
>
> In some of the other patches I have been sending, we have the same
> situation. I those, I have opted to just ignore the return value from
> dma_buf_end_cpu_access(). e.g...
>
>
> if (import_attach)
> dma_buf_end_cpu_access(import_attach->dmabuf, DMA_FROM_DEVICE);
>
> Is this a reasonable thing to do?
mipi_dbi_buf_copy() can be used by other rgb565 controllers, hence
the format check I think. So when that happens, it can be moved to
tinydrm-helpers.
Currently it's not possible to get an illegal format, since mipi-dbi
only supports those two formats.
Userspace can't set an illegal format, beacuse it's checked:
drm_atomic_commit -> drm_atomic_check_only -> drm_atomic_plane_check ->
drm_plane_check_pixel_format
So I think we can just leave this alone, or put the check before
import_attach if you really want to put this straight.
Noralf.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] drm/tinydrm: mipi-dbi: Fix unbalanced DMA access
2017-08-04 6:49 ` Noralf Trønnes
@ 2017-08-07 18:00 ` David Lechner
0 siblings, 0 replies; 7+ messages in thread
From: David Lechner @ 2017-08-07 18:00 UTC (permalink / raw)
To: Noralf Trønnes, dri-devel; +Cc: David Airlie, linux-kernel
On 08/04/2017 01:49 AM, Noralf Trønnes wrote:
>
> Den 04.08.2017 00.41, skrev David Lechner:
>> On 08/01/2017 03:14 PM, David Lechner wrote:
>>> If we return here and import_attach is true, then
>>> dma_buf_end_cpu_access()
>>> will not be called balance dma_buf_begin_cpu_access().
>>>
>>> Fix by setting ret instead of returning.
>>>
>>> Signed-off-by: David Lechner <david@lechnology.com>
>>> ---
>>> drivers/gpu/drm/tinydrm/mipi-dbi.c | 3 ++-
>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c
>>> b/drivers/gpu/drm/tinydrm/mipi-dbi.c
>>> index c83eeb7..e10fa4b 100644
>>> --- a/drivers/gpu/drm/tinydrm/mipi-dbi.c
>>> +++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
>>> @@ -183,7 +183,8 @@ static int mipi_dbi_buf_copy(void *dst, struct
>>> drm_framebuffer *fb,
>>> dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
>>> drm_get_format_name(fb->format->format,
>>> &format_name));
>>> - return -EINVAL;
>>> + ret = -EINVAL;
>>> + break;
>>> }
>>> if (import_attach)
>>>
>>
>>
>> I just realized that the next line here can mask ret.
>>
>>
>> if (import_attach)
>> ret = dma_buf_end_cpu_access(import_attach->dmabuf,
>> DMA_FROM_DEVICE);
>>
>> So, we should either ignore the return value from
>> dma_buf_end_cpu_access() always or add some logic to ignore it if ret
>> is already an error.
>>
>> In some of the other patches I have been sending, we have the same
>> situation. I those, I have opted to just ignore the return value from
>> dma_buf_end_cpu_access(). e.g...
>>
>>
>> if (import_attach)
>> dma_buf_end_cpu_access(import_attach->dmabuf, DMA_FROM_DEVICE);
>>
>> Is this a reasonable thing to do?
>
> mipi_dbi_buf_copy() can be used by other rgb565 controllers, hence
> the format check I think. So when that happens, it can be moved to
> tinydrm-helpers.
>
> Currently it's not possible to get an illegal format, since mipi-dbi
> only supports those two formats.
> Userspace can't set an illegal format, beacuse it's checked:
> drm_atomic_commit -> drm_atomic_check_only -> drm_atomic_plane_check ->
> drm_plane_check_pixel_format
>
> So I think we can just leave this alone, or put the check before
> import_attach if you really want to put this straight.
>
I guess we can just leave it alone for now.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2017-08-07 18:00 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-08-01 20:14 [PATCH] drm/tinydrm: mipi-dbi: Fix unbalanced DMA access David Lechner
2017-08-01 20:14 ` David Lechner
2017-08-02 18:51 ` Noralf Trønnes
2017-08-02 18:51 ` Noralf Trønnes
2017-08-03 22:41 ` David Lechner
2017-08-04 6:49 ` Noralf Trønnes
2017-08-07 18:00 ` David Lechner
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