diff mbox series

[v7,4/7] drm/log: Do not draw if drm_master is taken

Message ID 20241108082025.1004653-5-jfalempe@redhat.com (mailing list archive)
State New
Headers show
Series drm/log: Introduce a new boot logger to draw the kmsg on the screen | expand

Commit Message

Jocelyn Falempe Nov. 8, 2024, 8:10 a.m. UTC
When userspace takes drm_master, the drm_client buffer is no more
visible, so drm_log shouldn't waste CPU cycle to draw on it.

Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
---
 drivers/gpu/drm/drm_log.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

Comments

Thomas Zimmermann Nov. 8, 2024, 1:33 p.m. UTC | #1
Hi

Am 08.11.24 um 09:10 schrieb Jocelyn Falempe:
> When userspace takes drm_master, the drm_client buffer is no more
> visible, so drm_log shouldn't waste CPU cycle to draw on it.
>
> Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
> ---
>   drivers/gpu/drm/drm_log.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_log.c b/drivers/gpu/drm/drm_log.c
> index 376ee173d99d9..226e206e8b6a3 100644
> --- a/drivers/gpu/drm/drm_log.c
> +++ b/drivers/gpu/drm/drm_log.c
> @@ -18,6 +18,7 @@
>   #include <drm/drm_print.h>
>   
>   #include "drm_draw.h"
> +#include "drm_internal.h"
>   #include "drm_log.h"
>   
>   MODULE_AUTHOR("Jocelyn Falempe");
> @@ -308,8 +309,13 @@ static void drm_log_write_thread(struct console *con, struct nbcon_write_context
>   	if (!dlog->probed)
>   		drm_log_init_client(dlog);
>   
> -	for (i = 0; i < dlog->n_scanout; i++)
> -		drm_log_draw_kmsg_record(&dlog->scanout[i], wctxt->outbuf, wctxt->len);
> +	/* Check that we are still the master before drawing */
> +	if (drm_master_internal_acquire(dlog->client.dev)) {

Just a note: it would be better to track this state in the client code 
and handle these locks automatically. But it's ok for now. It would 
require an overhaul of the fbdev helpers as well.

> +		drm_master_internal_release(dlog->client.dev);

Don't you have to release after drawing?

Best regards
Thomas


> +
> +		for (i = 0; i < dlog->n_scanout; i++)
> +			drm_log_draw_kmsg_record(&dlog->scanout[i], wctxt->outbuf, wctxt->len);
> +	}
>   }
>   
>   static void drm_log_lock(struct console *con, unsigned long *flags)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_log.c b/drivers/gpu/drm/drm_log.c
index 376ee173d99d9..226e206e8b6a3 100644
--- a/drivers/gpu/drm/drm_log.c
+++ b/drivers/gpu/drm/drm_log.c
@@ -18,6 +18,7 @@ 
 #include <drm/drm_print.h>
 
 #include "drm_draw.h"
+#include "drm_internal.h"
 #include "drm_log.h"
 
 MODULE_AUTHOR("Jocelyn Falempe");
@@ -308,8 +309,13 @@  static void drm_log_write_thread(struct console *con, struct nbcon_write_context
 	if (!dlog->probed)
 		drm_log_init_client(dlog);
 
-	for (i = 0; i < dlog->n_scanout; i++)
-		drm_log_draw_kmsg_record(&dlog->scanout[i], wctxt->outbuf, wctxt->len);
+	/* Check that we are still the master before drawing */
+	if (drm_master_internal_acquire(dlog->client.dev)) {
+		drm_master_internal_release(dlog->client.dev);
+
+		for (i = 0; i < dlog->n_scanout; i++)
+			drm_log_draw_kmsg_record(&dlog->scanout[i], wctxt->outbuf, wctxt->len);
+	}
 }
 
 static void drm_log_lock(struct console *con, unsigned long *flags)