| Message ID | 1481853578-19834-1-git-send-email-hofrat@osadl.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 16 Dec 2016, Nicholas Mc Guire <hofrat@osadl.org> wrote: > udelay_range(1, 2) is inefficient and as discussions with Jani Nikula > <jani.nikula@linux.intel.com> unnecessary here. This replaces this > tight setting with a relaxed delay of min=20 and max=50 which helps > the hrtimer subsystem optimize timer handling. > > Fixes: commit be4fc046bed3 ("drm/i915: add VLV DSI PLL Calculations") > Link: http://lkml.org/lkml/2016/12/15/147 > Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Pushed to drm-intel-next-queued, thanks for the patch. BR, Jani. > --- > > V2: use relaxed uslee_range() rather than udelay > fix documentation of changed timings > > Problem found by coccinelle: > > Patch was compile tested with: x86_64_defconfig (implies CONFIG_DRM_I915) > > Patch is against 4.9.0 (localversion-next is next-20161215) > > drivers/gpu/drm/i915/intel_dsi_pll.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c > index 56eff60..d210bc4 100644 > --- a/drivers/gpu/drm/i915/intel_dsi_pll.c > +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c > @@ -156,8 +156,10 @@ static void vlv_enable_dsi_pll(struct intel_encoder *encoder, > vlv_cck_write(dev_priv, CCK_REG_DSI_PLL_CONTROL, > config->dsi_pll.ctrl & ~DSI_PLL_VCO_EN); > > - /* wait at least 0.5 us after ungating before enabling VCO */ > - usleep_range(1, 10); > + /* wait at least 0.5 us after ungating before enabling VCO, > + * allow hrtimer subsystem optimization by relaxing timing > + */ > + usleep_range(10, 50); > > vlv_cck_write(dev_priv, CCK_REG_DSI_PLL_CONTROL, config->dsi_pll.ctrl);
diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c index 56eff60..d210bc4 100644 --- a/drivers/gpu/drm/i915/intel_dsi_pll.c +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c @@ -156,8 +156,10 @@ static void vlv_enable_dsi_pll(struct intel_encoder *encoder, vlv_cck_write(dev_priv, CCK_REG_DSI_PLL_CONTROL, config->dsi_pll.ctrl & ~DSI_PLL_VCO_EN); - /* wait at least 0.5 us after ungating before enabling VCO */ - usleep_range(1, 10); + /* wait at least 0.5 us after ungating before enabling VCO, + * allow hrtimer subsystem optimization by relaxing timing + */ + usleep_range(10, 50); vlv_cck_write(dev_priv, CCK_REG_DSI_PLL_CONTROL, config->dsi_pll.ctrl);
udelay_range(1, 2) is inefficient and as discussions with Jani Nikula <jani.nikula@linux.intel.com> unnecessary here. This replaces this tight setting with a relaxed delay of min=20 and max=50 which helps the hrtimer subsystem optimize timer handling. Fixes: commit be4fc046bed3 ("drm/i915: add VLV DSI PLL Calculations") Link: http://lkml.org/lkml/2016/12/15/147 Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> --- V2: use relaxed uslee_range() rather than udelay fix documentation of changed timings Problem found by coccinelle: Patch was compile tested with: x86_64_defconfig (implies CONFIG_DRM_I915) Patch is against 4.9.0 (localversion-next is next-20161215) drivers/gpu/drm/i915/intel_dsi_pll.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)