| 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 |
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)
On 08/11/2024 14:33, Thomas Zimmermann wrote: > 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? I'm not sure, the drawing code will only call drm_client_buffer_vmap_local() / unmap and drm_client_framebuffer_flush(), and they don't require the master lock to be taken. I think master lock is needed only for modesetting. Also the dlog->lock is taken by the console thread, so there are no race conditions with the drm_client callbacks (hotplug/suspend/resume). > > 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 --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)
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(-)