drm: Use raw monotonic clock
Subsystems (2)
PATCH 1/1 drm: Use raw monotonic clock
Wall time obtained from do_gettimeofday is susceptible to sudden jumps due to user setting the time or due to NTP.
Raw monotonic time is constantly increasing time and isn't affected by NTP adjustments better suited for comparing two timestamps in short intervals.
Signed-off-by Abhilash Jindal <[email protected]>
--- drivers/gpu/drm/via/via_drv.h | 2 +- drivers/gpu/drm/via/via_irq.c | 14 +++----------- 2 files changed, 4 insertions(+), 12 deletions(-)
drivers/gpu/drm/via/via_drv.h +1 -1
@@ -74,7 +74,7 @@ typedef struct drm_via_private {volatile uint32_t *last_pause_ptr;volatile uint32_t *hw_addr_ptr;drm_via_ring_buffer_t ring; -struct timeval last_vblank; +ktime_t last_vblank;int last_vblank_valid;unsigned usec_per_vblank;atomic_t vbl_received;
drivers/gpu/drm/via/via_irq.c +3 -11
@@ -88,13 +88,6 @@ static int via_num_unichrome = ARRAY_SIZE(via_unichrome_irqs);static int via_irqmap_unichrome[] = {-1 ,-1 ,-1 ,0 ,-1 ,1 }; -static unsigned time_diff (struct timeval *now,struct timeval *then) -{ -return (now->tv_usec >= then->tv_usec) ? - now->tv_usec - then->tv_usec : -1000000 - (then->tv_usec - now->tv_usec); -} -u32 via_get_vblank_counter (struct drm_device *dev,int crtc) {drm_via_private_t *dev_priv = dev->dev_private;
@@ -110,7 +103,7 @@ irqreturn_t via_driver_irq_handler(int irq, void *arg)drm_via_private_t *dev_priv = (drm_via_private_t *) dev->dev_private;u32 status;int handled =0 ; -struct timeval cur_vblank; +ktime_t cur_vblank;drm_via_irq_t *cur_irq = dev_priv->via_irqs;int i;
@@ -118,11 +111,10 @@ irqreturn_t via_driver_irq_handler(int irq, void *arg)if (status &VIA_IRQ_VBLANK_PENDING ) {atomic_inc (&dev_priv->vbl_received);if (!(atomic_read (&dev_priv->vbl_received) &0x0F )) { -do_gettimeofday (&cur_vblank); + cur_vblank =ktime_get_raw ();if (dev_priv->last_vblank_valid) { dev_priv->usec_per_vblank = -time_diff (&cur_vblank, - &dev_priv->last_vblank) >>4 ; +ktime_to_us (ktime_sub (cur_vblank, dev_priv->last_vblank)) >>4 ; } dev_priv->last_vblank = cur_vblank; dev_priv->last_vblank_valid =1 ;
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1.7.9.5 _______________________________________________ dri-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/dri-devel
Quoted 7 lines · Abhilash Jindal
Wall time obtained from
do_gettimeofdayis susceptible to sudden jumps due to user setting the time or due to NTP.Raw monotonic time is constantly increasing time and isn't affected by NTP adjustments better suited for comparing two timestamps in short intervals.
Signed-off-by Abhilash Jindal <[email protected]>
Do you actually have a via card supported by this driver, including the corresponding userspace stack? Note that the userspace opengl driver for this has been nuked in upstream mesa years ago ...
-Daniel
Quoted 66 lines
--- drivers/gpu/drm/via/via_drv.h | 2 +- drivers/gpu/drm/via/via_irq.c | 14 +++----------- 2 files changed, 4 insertions(+), 12 deletions(-)drivers/gpu/drm/via/via_drv.h +1
-1@@ -74,7 +74,7 @@ typedef struct drm_via_private {volatile uint32_t *last_pause_ptr;volatile uint32_t *hw_addr_ptr;drm_via_ring_buffer_t ring; -struct timeval last_vblank; +ktime_t last_vblank;int last_vblank_valid;unsigned usec_per_vblank;atomic_t vbl_received;drivers/gpu/drm/via/via_irq.c +3
-11@@ -88,13 +88,6 @@ static int via_num_unichrome = ARRAY_SIZE(via_unichrome_irqs);static int via_irqmap_unichrome[] = {-1 ,-1 ,-1 ,0 ,-1 ,1 }; -static unsigned time_diff (struct timeval *now,struct timeval *then) -{ -return (now->tv_usec >= then->tv_usec) ? - now->tv_usec - then->tv_usec : -1000000 - (then->tv_usec - now->tv_usec); -} -u32 via_get_vblank_counter (struct drm_device *dev,int crtc) {drm_via_private_t *dev_priv = dev->dev_private;@@ -110,7 +103,7 @@ irqreturn_t via_driver_irq_handler(int irq, void *arg)drm_via_private_t *dev_priv = (drm_via_private_t *) dev->dev_private;u32 status;int handled =0 ; -struct timeval cur_vblank; +ktime_t cur_vblank;drm_via_irq_t *cur_irq = dev_priv->via_irqs;int i;@@ -118,11 +111,10 @@ irqreturn_t via_driver_irq_handler(int irq, void *arg)if (status &VIA_IRQ_VBLANK_PENDING ) {atomic_inc (&dev_priv->vbl_received);if (!(atomic_read (&dev_priv->vbl_received) &0x0F )) { -do_gettimeofday (&cur_vblank); + cur_vblank =ktime_get_raw ();if (dev_priv->last_vblank_valid) { dev_priv->usec_per_vblank = -time_diff (&cur_vblank, - &dev_priv->last_vblank) >>4 ; +ktime_to_us (ktime_sub (cur_vblank, dev_priv->last_vblank)) >>4 ; } dev_priv->last_vblank = cur_vblank; dev_priv->last_vblank_valid =1 ;Signature · 6 lines
1.7.9.5 _______________________________________________ dri-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/dri-devel
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Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/dri-devel