From: Alon Ziv Date: Mon, 30 Jul 2007 22:47:59 +0300 Subject: [PATCH] Sane handling of timeouts in WaitForVerticalSync RADEONWaitForVerticalSync() and RADEONWaitForVerticalSync2() need to wait for a timeout specified in milliseconds; looping around usleep() causes the timeout to be unnecessarily long, as the OS may sleep longer than requested (on Linux the minimum actual sleep value is 10ms). The new logic uses gettimeofday() in the loop to see when the (absolute) timeout has arrived. Signed-off-by: Alon Ziv --- src/radeon.h | 19 +++++++++++++++++++ src/radeon_driver.c | 20 ++++++++++---------- 2 files changed, 29 insertions(+), 10 deletions(-) diff --git a/src/radeon.h b/src/radeon.h index a22e481..58f6bab 100644 --- a/src/radeon.h +++ b/src/radeon.h @@ -189,6 +189,8 @@ typedef struct _region { #define RADEON_IDLE_RETRY 16 /* Fall out of idle loops after this count */ #define RADEON_TIMEOUT 2000000 /* Fall out of wait loops after this count */ +#define RADEON_VSYNC_TIMEOUT 20000 /* Maximum wait for VSYNC (in usecs) */ + /* Buffer are aligned on 4096 byte boundaries */ #define RADEON_BUFFER_ALIGN 0x00000fff #define RADEON_VBIOS_SIZE 0x00010000 @@ -1178,4 +1180,21 @@ static __inline__ void RADEON_SYNC(RADEONInfoPtr info, ScrnInfoPtr pScrn) #endif } +static __inline__ void radeon_init_timeout(struct timeval *endtime, + unsigned int timeout) +{ + gettimeofday(endtime, NULL); + endtime->tv_usec += timeout; + endtime->tv_sec += endtime->tv_usec / 1000000; + endtime->tv_usec %= 1000000; +} + +static __inline__ int radeon_timedout(const struct timeval *endtime) +{ + struct timeval now; + gettimeofday(&now, NULL); + return now.tv_sec == endtime->tv_sec ? + now.tv_usec > endtime->tv_usec : now.tv_sec > endtime->tv_sec; +} + #endif /* _RADEON_H_ */ diff --git a/src/radeon_driver.c b/src/radeon_driver.c index 5c20b0e..b6755a8 100644 --- a/src/radeon_driver.c +++ b/src/radeon_driver.c @@ -759,7 +759,7 @@ void RADEONWaitForVerticalSync(ScrnInfoPtr pScrn) RADEONInfoPtr info = RADEONPTR(pScrn); unsigned char *RADEONMMIO = info->MMIO; CARD32 crtc_gen_cntl; - int i; + struct timeval timeout; crtc_gen_cntl = INREG(RADEON_CRTC_GEN_CNTL); if ((crtc_gen_cntl & RADEON_CRTC_DISP_REQ_EN_B) || @@ -770,10 +770,10 @@ void RADEONWaitForVerticalSync(ScrnInfoPtr pScrn) OUTREG(RADEON_CRTC_STATUS, RADEON_CRTC_VBLANK_SAVE_CLEAR); /* Wait for it to go back up */ - for (i = 0; i < RADEON_TIMEOUT/1000; i++) { - if (INREG(RADEON_CRTC_STATUS) & RADEON_CRTC_VBLANK_SAVE) break; - usleep(1); - } + radeon_init_timeout(&timeout, RADEON_VSYNC_TIMEOUT); + while (!(INREG(RADEON_CRTC_STATUS) & RADEON_CRTC_VBLANK_SAVE) && + !radeon_timedout(&timeout)) + usleep(100); } /* Wait for vertical sync on secondary CRTC */ @@ -782,7 +782,7 @@ void RADEONWaitForVerticalSync2(ScrnInfoPtr pScrn) RADEONInfoPtr info = RADEONPTR(pScrn); unsigned char *RADEONMMIO = info->MMIO; CARD32 crtc2_gen_cntl; - int i; + struct timeval timeout; crtc2_gen_cntl = INREG(RADEON_CRTC2_GEN_CNTL); if ((crtc2_gen_cntl & RADEON_CRTC2_DISP_REQ_EN_B) || @@ -793,10 +793,10 @@ void RADEONWaitForVerticalSync2(ScrnInfoPtr pScrn) OUTREG(RADEON_CRTC2_STATUS, RADEON_CRTC2_VBLANK_SAVE_CLEAR); /* Wait for it to go back up */ - for (i = 0; i < RADEON_TIMEOUT/1000; i++) { - if (INREG(RADEON_CRTC2_STATUS) & RADEON_CRTC2_VBLANK_SAVE) break; - usleep(1); - } + radeon_init_timeout(&timeout, RADEON_VSYNC_TIMEOUT); + while (!(INREG(RADEON_CRTC2_STATUS) & RADEON_CRTC2_VBLANK_SAVE) && + !radeon_timedout(&timeout)) + usleep(100); }