On Wed, Mar 28, 2012 at 9:05 PM, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > On Wed, 28 Mar 2012 20:51:57 +0800, Daniel Kurtz <djkurtz@xxxxxxxxxxxx> wrote: >> The POSTING_READ() calls were originally added to make sure the writes >> were flushed before any timing delays and across loops. >> However, the normal I915_READ() and I915_WRITE() macros already call >> readl() / writel(), which already have an explicit mb(). >> >> Now that the code has settled a bit, let's remove them. >> >> Signed-off-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx> >> --- >> drivers/gpu/drm/i915/intel_i2c.c | 5 ----- >> 1 files changed, 0 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c >> index 2865313..be2852e 100644 >> --- a/drivers/gpu/drm/i915/intel_i2c.c >> +++ b/drivers/gpu/drm/i915/intel_i2c.c >> @@ -131,7 +131,6 @@ static void set_clock(void *data, int state_high) >> GPIO_CLOCK_VAL_MASK; >> >> I915_WRITE_NOTRACE(bus->gpio_reg, reserved | clock_bits); >> - POSTING_READ(bus->gpio_reg); > We do need the write flush here (and set_data) as the next action is a > udelay loop which is not per-se a mb. Now I am confused. I915_WRITE_NOTRACE() calls writel(), which has an explicit mb(); Why do you need another mb? > -Chris > > -- > Chris Wilson, Intel Open Source Technology Centre _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
