[PATCH v3 0/3] drm/i915: Fix header test and log spam on !x86

[PATCH v3 0/3] drm/i915: Fix header test and log spam on !x86

[Lucas De Marchi]

Some minor fixes and changes to help porting i915 to arm64, or even
anything !x86.

v3: No changes, just submit to the right mailing list.

Lucas De Marchi (3):
  drm: Stop spamming log with drm_cache message
  drm/i915: Fix header test for !CONFIG_X86
  drm/i915: Do not spam log with missing arch support

 drivers/gpu/drm/drm_cache.c    | 9 +++------
 drivers/gpu/drm/i915/i915_mm.h | 4 ++--
 2 files changed, 5 insertions(+), 8 deletions(-)

-- 
2.35.0

[PATCH v3 1/3] drm: Stop spamming log with drm_cache message

[Lucas De Marchi]

Only x86 and in some cases PPC have support added in drm_cache.c for the
clflush class of functions. However warning once is sufficient to taint
the log instead of spamming it with "Architecture has no drm_cache.c
support" every few millisecond. Switch to WARN_ONCE() so we still get
the log message, but only once, together with the warning. E.g:

	------------[ cut here ]------------
	Architecture has no drm_cache.c support
	WARNING: CPU: 80 PID: 888 at drivers/gpu/drm/drm_cache.c:139 drm_clflush_sg+0x40/0x50 [drm]
	...

v2 (Jani): use WARN_ONCE() and keep the message previously on pr_err()

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
---

v3: No changes from previous version, just submitting to the right
mailing list

 drivers/gpu/drm/drm_cache.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index f19d9acbe959..2c3fa5677f7e 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -112,8 +112,7 @@ drm_clflush_pages(struct page *pages[], unsigned long num_pages)
 		kunmap_atomic(page_virtual);
 	}
 #else
-	pr_err("Architecture has no drm_cache.c support\n");
-	WARN_ON_ONCE(1);
+	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
 #endif
 }
 EXPORT_SYMBOL(drm_clflush_pages);
@@ -143,8 +142,7 @@ drm_clflush_sg(struct sg_table *st)
 	if (wbinvd_on_all_cpus())
 		pr_err("Timed out waiting for cache flush\n");
 #else
-	pr_err("Architecture has no drm_cache.c support\n");
-	WARN_ON_ONCE(1);
+	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
 #endif
 }
 EXPORT_SYMBOL(drm_clflush_sg);
@@ -177,8 +175,7 @@ drm_clflush_virt_range(void *addr, unsigned long length)
 	if (wbinvd_on_all_cpus())
 		pr_err("Timed out waiting for cache flush\n");
 #else
-	pr_err("Architecture has no drm_cache.c support\n");
-	WARN_ON_ONCE(1);
+	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
 #endif
 }
 EXPORT_SYMBOL(drm_clflush_virt_range);
-- 
2.35.0

Re: [PATCH v3 1/3] drm: Stop spamming log with drm_cache message

[Souza, Jose]

On Mon, 2022-01-31 at 08:59 -0800, Lucas De Marchi wrote:
> Only x86 and in some cases PPC have support added in drm_cache.c for the
> clflush class of functions. However warning once is sufficient to taint
> the log instead of spamming it with "Architecture has no drm_cache.c
> support" every few millisecond. Switch to WARN_ONCE() so we still get
> the log message, but only once, together with the warning. E.g:
> 
> 	------------[ cut here ]------------
> 	Architecture has no drm_cache.c support
> 	WARNING: CPU: 80 PID: 888 at drivers/gpu/drm/drm_cache.c:139 drm_clflush_sg+0x40/0x50 [drm]
> 	...
> 
> v2 (Jani): use WARN_ONCE() and keep the message previously on pr_err()

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>

But while at it, why not add a drm_device parameter to this function so we can use drm_WARN_ONCE()?
Anyways, it is better than before.

> 
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <mripard@kernel.org>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
> 
> v3: No changes from previous version, just submitting to the right
> mailing list
> 
>  drivers/gpu/drm/drm_cache.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
> index f19d9acbe959..2c3fa5677f7e 100644
> --- a/drivers/gpu/drm/drm_cache.c
> +++ b/drivers/gpu/drm/drm_cache.c
> @@ -112,8 +112,7 @@ drm_clflush_pages(struct page *pages[], unsigned long num_pages)
>  		kunmap_atomic(page_virtual);
>  	}
>  #else
> -	pr_err("Architecture has no drm_cache.c support\n");
> -	WARN_ON_ONCE(1);
> +	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
>  #endif
>  }
>  EXPORT_SYMBOL(drm_clflush_pages);
> @@ -143,8 +142,7 @@ drm_clflush_sg(struct sg_table *st)
>  	if (wbinvd_on_all_cpus())
>  		pr_err("Timed out waiting for cache flush\n");
>  #else
> -	pr_err("Architecture has no drm_cache.c support\n");
> -	WARN_ON_ONCE(1);
> +	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
>  #endif
>  }
>  EXPORT_SYMBOL(drm_clflush_sg);
> @@ -177,8 +175,7 @@ drm_clflush_virt_range(void *addr, unsigned long length)
>  	if (wbinvd_on_all_cpus())
>  		pr_err("Timed out waiting for cache flush\n");
>  #else
> -	pr_err("Architecture has no drm_cache.c support\n");
> -	WARN_ON_ONCE(1);
> +	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
>  #endif
>  }
>  EXPORT_SYMBOL(drm_clflush_virt_range);

Re: [PATCH v3 1/3] drm: Stop spamming log with drm_cache message

[Lucas De Marchi]

On Tue, Feb 01, 2022 at 09:12:05AM -0800, Jose Souza wrote:
>On Mon, 2022-01-31 at 08:59 -0800, Lucas De Marchi wrote:
>> Only x86 and in some cases PPC have support added in drm_cache.c for the
>> clflush class of functions. However warning once is sufficient to taint
>> the log instead of spamming it with "Architecture has no drm_cache.c
>> support" every few millisecond. Switch to WARN_ONCE() so we still get
>> the log message, but only once, together with the warning. E.g:
>>
>> 	------------[ cut here ]------------
>> 	Architecture has no drm_cache.c support
>> 	WARNING: CPU: 80 PID: 888 at drivers/gpu/drm/drm_cache.c:139 drm_clflush_sg+0x40/0x50 [drm]
>> 	...
>>
>> v2 (Jani): use WARN_ONCE() and keep the message previously on pr_err()
>
>Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
>
>But while at it, why not add a drm_device parameter to this function so we can use drm_WARN_ONCE()?
>Anyways, it is better than before.

I thought about that, but it didn't seem justifiable because:

1) drm_WARN_ONCE will basically add dev_driver_string() to the log.
However the warning message here is basically helping the bootstrap of
additional archs. They shouldn't be seen on anything properly supported.

2) This seems all to be a layer below drm anyway and could even be used
in places outside easy access to a drm pointer.

So, it seems the benefit of using the subsystem-specific drm_WARN_ONCE
doesn't justify the hassle of changing the callers, possibly adding
additional back pointers to have access to the drm device pointer.

thanks
Lucas De Marchi

Re: [Intel-gfx] [PATCH v3 1/3] drm: Stop spamming log with drm_cache message

[Rodrigo Vivi]

On Tue, Feb 01, 2022 at 09:41:33AM -0800, Lucas De Marchi wrote:
> On Tue, Feb 01, 2022 at 09:12:05AM -0800, Jose Souza wrote:
> > On Mon, 2022-01-31 at 08:59 -0800, Lucas De Marchi wrote:
> > > Only x86 and in some cases PPC have support added in drm_cache.c for the
> > > clflush class of functions. However warning once is sufficient to taint
> > > the log instead of spamming it with "Architecture has no drm_cache.c
> > > support" every few millisecond. Switch to WARN_ONCE() so we still get
> > > the log message, but only once, together with the warning. E.g:
> > > 
> > > 	------------[ cut here ]------------
> > > 	Architecture has no drm_cache.c support
> > > 	WARNING: CPU: 80 PID: 888 at drivers/gpu/drm/drm_cache.c:139 drm_clflush_sg+0x40/0x50 [drm]
> > > 	...
> > > 
> > > v2 (Jani): use WARN_ONCE() and keep the message previously on pr_err()
> > 
> > Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
> > 
> > But while at it, why not add a drm_device parameter to this function so we can use drm_WARN_ONCE()?
> > Anyways, it is better than before.
> 
> I thought about that, but it didn't seem justifiable because:
> 
> 1) drm_WARN_ONCE will basically add dev_driver_string() to the log.
> However the warning message here is basically helping the bootstrap of
> additional archs. They shouldn't be seen on anything properly supported.
> 
> 2) This seems all to be a layer below drm anyway and could even be used
> in places outside easy access to a drm pointer.
> 
> So, it seems the benefit of using the subsystem-specific drm_WARN_ONCE
> doesn't justify the hassle of changing the callers, possibly adding
> additional back pointers to have access to the drm device pointer.

Initially I had same feeling as Jose, but good points raised here.

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> 
> thanks
> Lucas De Marchi

[PATCH v3 2/3] drm/i915: Fix header test for !CONFIG_X86

[Lucas De Marchi]

Architectures others than x86 have a stub implementation calling
WARN_ON_ONCE(). The appropriate headers need to be included, otherwise
the header-test target will fail with:

  HDRTEST drivers/gpu/drm/i915/i915_mm.h
In file included from <command-line>:
./drivers/gpu/drm/i915/i915_mm.h: In function ‘remap_io_mapping’:
./drivers/gpu/drm/i915/i915_mm.h:26:2: error: implicit declaration of function ‘WARN_ON_ONCE’ [-Werror=implicit-function-declaration]
   26 |  WARN_ON_ONCE(1);
      |  ^~~~~~~~~~~~

v2: Do not include <linux/printk.h> since call to pr_err() has been
removed

Fixes: 67c430bbaae1 ("drm/i915: Skip remap_io_mapping() for non-x86 platforms")
Cc: Siva Mullati <siva.mullati@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
---

v3: No changes from previous version, just submitting to the right
mailing list

 drivers/gpu/drm/i915/i915_mm.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/i915_mm.h b/drivers/gpu/drm/i915/i915_mm.h
index 76f1d53bdf34..3ad22bbe80eb 100644
--- a/drivers/gpu/drm/i915/i915_mm.h
+++ b/drivers/gpu/drm/i915/i915_mm.h
@@ -6,6 +6,7 @@
 #ifndef __I915_MM_H__
 #define __I915_MM_H__
 
+#include <linux/bug.h>
 #include <linux/types.h>
 
 struct vm_area_struct;
-- 
2.35.0

Re: [PATCH v3 2/3] drm/i915: Fix header test for !CONFIG_X86

[Siva Mullati]

Reviewed-by: Siva Mullati <siva.mullati@intel.com>

On 31/01/22 10:29 pm, Lucas De Marchi wrote:
> Architectures others than x86 have a stub implementation calling
> WARN_ON_ONCE(). The appropriate headers need to be included, otherwise
> the header-test target will fail with:
>
>   HDRTEST drivers/gpu/drm/i915/i915_mm.h
> In file included from <command-line>:
> ./drivers/gpu/drm/i915/i915_mm.h: In function ‘remap_io_mapping’:
> ./drivers/gpu/drm/i915/i915_mm.h:26:2: error: implicit declaration of function ‘WARN_ON_ONCE’ [-Werror=implicit-function-declaration]
>    26 |  WARN_ON_ONCE(1);
>       |  ^~~~~~~~~~~~
>
> v2: Do not include <linux/printk.h> since call to pr_err() has been
> removed
>
> Fixes: 67c430bbaae1 ("drm/i915: Skip remap_io_mapping() for non-x86 platforms")
> Cc: Siva Mullati <siva.mullati@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
>
> v3: No changes from previous version, just submitting to the right
> mailing list
>
>  drivers/gpu/drm/i915/i915_mm.h | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_mm.h b/drivers/gpu/drm/i915/i915_mm.h
> index 76f1d53bdf34..3ad22bbe80eb 100644
> --- a/drivers/gpu/drm/i915/i915_mm.h
> +++ b/drivers/gpu/drm/i915/i915_mm.h
> @@ -6,6 +6,7 @@
>  #ifndef __I915_MM_H__
>  #define __I915_MM_H__
>  
> +#include <linux/bug.h>
>  #include <linux/types.h>
>  
>  struct vm_area_struct;

Re: [PATCH v3 2/3] drm/i915: Fix header test for !CONFIG_X86

[Souza, Jose]

On Mon, 2022-01-31 at 08:59 -0800, Lucas De Marchi wrote:
> Architectures others than x86 have a stub implementation calling
> WARN_ON_ONCE(). The appropriate headers need to be included, otherwise
> the header-test target will fail with:
> 
>   HDRTEST drivers/gpu/drm/i915/i915_mm.h
> In file included from <command-line>:
> ./drivers/gpu/drm/i915/i915_mm.h: In function ‘remap_io_mapping’:
> ./drivers/gpu/drm/i915/i915_mm.h:26:2: error: implicit declaration of function ‘WARN_ON_ONCE’ [-Werror=implicit-function-declaration]
>    26 |  WARN_ON_ONCE(1);
>       |  ^~~~~~~~~~~~
> 
> v2: Do not include <linux/printk.h> since call to pr_err() has been
> removed

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>

> 
> Fixes: 67c430bbaae1 ("drm/i915: Skip remap_io_mapping() for non-x86 platforms")
> Cc: Siva Mullati <siva.mullati@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
> 
> v3: No changes from previous version, just submitting to the right
> mailing list
> 
>  drivers/gpu/drm/i915/i915_mm.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_mm.h b/drivers/gpu/drm/i915/i915_mm.h
> index 76f1d53bdf34..3ad22bbe80eb 100644
> --- a/drivers/gpu/drm/i915/i915_mm.h
> +++ b/drivers/gpu/drm/i915/i915_mm.h
> @@ -6,6 +6,7 @@
>  #ifndef __I915_MM_H__
>  #define __I915_MM_H__
>  
> +#include <linux/bug.h>
>  #include <linux/types.h>
>  
>  struct vm_area_struct;

[PATCH v3 3/3] drm/i915: Do not spam log with missing arch support

[Lucas De Marchi]

Following what was done in drm_cache.c, when the stub for
remap_io_mapping() was added in commit 67c430bbaae1 ("drm/i915: Skip
remap_io_mapping() for non-x86 platforms"), it included a log message
with pr_err().  However just the warning is already enough and switching
to WARN_ONCE() allows us to keep the log message while avoiding log
spam.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
---

v3: No changes from previous version, just submitting to the right
mailing list

 drivers/gpu/drm/i915/i915_mm.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_mm.h b/drivers/gpu/drm/i915/i915_mm.h
index 3ad22bbe80eb..04c8974d822b 100644
--- a/drivers/gpu/drm/i915/i915_mm.h
+++ b/drivers/gpu/drm/i915/i915_mm.h
@@ -23,8 +23,7 @@ int remap_io_mapping(struct vm_area_struct *vma,
 		     unsigned long addr, unsigned long pfn, unsigned long size,
 		     struct io_mapping *iomap)
 {
-	pr_err("Architecture has no %s() and shouldn't be calling this function\n", __func__);
-	WARN_ON_ONCE(1);
+	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
 	return 0;
 }
 #endif
-- 
2.35.0

Re: [Intel-gfx] [PATCH v3 3/3] drm/i915: Do not spam log with missing arch support

[Souza, Jose]

On Mon, 2022-01-31 at 08:59 -0800, Lucas De Marchi wrote:
> Following what was done in drm_cache.c, when the stub for
> remap_io_mapping() was added in commit 67c430bbaae1 ("drm/i915: Skip
> remap_io_mapping() for non-x86 platforms"), it included a log message
> with pr_err().  However just the warning is already enough and switching
> to WARN_ONCE() allows us to keep the log message while avoiding log
> spam.

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>

But same suggestion as the first patch in this series about drm_WARN_ONCE().

> 
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
> 
> v3: No changes from previous version, just submitting to the right
> mailing list
> 
>  drivers/gpu/drm/i915/i915_mm.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_mm.h b/drivers/gpu/drm/i915/i915_mm.h
> index 3ad22bbe80eb..04c8974d822b 100644
> --- a/drivers/gpu/drm/i915/i915_mm.h
> +++ b/drivers/gpu/drm/i915/i915_mm.h
> @@ -23,8 +23,7 @@ int remap_io_mapping(struct vm_area_struct *vma,
>  		     unsigned long addr, unsigned long pfn, unsigned long size,
>  		     struct io_mapping *iomap)
>  {
> -	pr_err("Architecture has no %s() and shouldn't be calling this function\n", __func__);
> -	WARN_ON_ONCE(1);
> +	WARN_ONCE(1, "Architecture has no drm_cache.c support\n");
>  	return 0;
>  }
>  #endif