On Thu, Apr 18, 2013 at 10:10:46AM +0200, Daniel Vetter wrote:
> On Wed, Apr 17, 2013 at 03:55:00PM -0700, Jesse Barnes wrote:
> > From: Pallavi G <pallavi.g at intel.com>
> >
> > For high res modes m n p calculation is fixed for VLV platform.
> >
> > v2: use 64 bit types and math (Ville)
> >
> > Signed-off-by: Pallavi G <pallavi.g at intel.com>
> > Signed-off-by: Vijay Purushothaman <vijay.a.purushothaman at intel.com>
> > Signed-off-by: Yogesh M <yogesh.mohan.marimuthu at intel.com>
> > Signed-off-by: Gajanan Bhat <gajanan.bhat at intel.com>
> > ---
> > drivers/gpu/drm/i915/intel_display.c | 25 +++++++++++++++----------
> > 1 file changed, 15 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 28b8fac..f3aa24f4 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -31,6 +31,7 @@
> > #include <linux/kernel.h>
> > #include <linux/slab.h>
> > #include <linux/vgaarb.h>
> > +#include <linux/math64.h>
> > #include <drm/drm_edid.h>
> > #include <drm/drmP.h>
> > #include "intel_drv.h"
> > @@ -396,21 +397,21 @@ static const intel_limit_t intel_limits_vlv_dac = {
> > .m1 = { .min = 2, .max = 3 },
> > .m2 = { .min = 11, .max = 156 },
> > .p = { .min = 10, .max = 30 },
> > - .p1 = { .min = 2, .max = 3 },
> > + .p1 = { .min = 1, .max = 3 },
> > .p2 = { .dot_limit = 270000,
> > .p2_slow = 2, .p2_fast = 20 },
> > .find_pll = intel_vlv_find_best_pll,
> > };
> >
> > static const intel_limit_t intel_limits_vlv_hdmi = {
> > - .dot = { .min = 20000, .max = 165000 },
> > - .vco = { .min = 4000000, .max = 5994000},
> > - .n = { .min = 1, .max = 7 },
> > + .dot = { .min = 25000, .max = 180000 },
> > + .vco = { .min = 4040000, .max = 5960000 },
> > + .n = { .min = 1, .max = 5 },
> > .m = { .min = 60, .max = 300 }, /* guess */
> > .m1 = { .min = 2, .max = 3 },
> > - .m2 = { .min = 11, .max = 156 },
> > + .m2 = { .min = 15, .max = 149 },
> > .p = { .min = 10, .max = 30 },
> > - .p1 = { .min = 2, .max = 3 },
> > + .p1 = { .min = 1, .max = 3 },
> > .p2 = { .dot_limit = 270000,
> > .p2_slow = 2, .p2_fast = 20 },
> > .find_pll = intel_vlv_find_best_pll,
> > @@ -424,7 +425,7 @@ static const intel_limit_t intel_limits_vlv_dp = {
> > .m1 = { .min = 2, .max = 3 },
> > .m2 = { .min = 11, .max = 156 },
> > .p = { .min = 10, .max = 30 },
> > - .p1 = { .min = 2, .max = 3 },
> > + .p1 = { .min = 1, .max = 3 },
> > .p2 = { .dot_limit = 270000,
> > .p2_slow = 2, .p2_fast = 20 },
> > .find_pll = intel_vlv_find_best_pll,
> > @@ -821,10 +822,13 @@ intel_vlv_find_best_pll(const intel_limit_t *limit, struct drm_crtc *crtc,
> > int target, int refclk, intel_clock_t *match_clock,
> > intel_clock_t *best_clock)
> > {
> > +#define LONG_OVERFLOW 0x7FFFFFFF
> > +#define DIFF_OVERFLOW (LONG_OVERFLOW/10000)
>
> Unused?
>
> > +
> > u32 p1, p2, m1, m2, vco, bestn, bestm1, bestm2, bestp1, bestp2;
> > u32 m, n, fastclk;
> > u32 updrate, minupdate, fracbits, p;
> > - unsigned long bestppm, ppm, absppm;
> > + s64 bestppm, ppm, absppm, ppmdiff;
> > int dotclk, flag;
> >
> > flag = 0;
> > @@ -853,8 +857,9 @@ intel_vlv_find_best_pll(const intel_limit_t *limit, struct drm_crtc *crtc,
> > m = m1 * m2;
> > vco = updrate * m;
> > if (vco >= limit->vco.min && vco < limit->vco.max) {
> > - ppm = 1000000 * ((vco / p) - fastclk) / fastclk;
> > - absppm = (ppm > 0) ? ppm : (-ppm);
> > + ppmdiff = div_s64((100*vco), p) - (100*fastclk);
>
> I'm probably a bit dense, but I think C integer conversion rules say
> (100*vco) is still only a u32. So I think that div_s64 doesn't help a lot
> since the upcast to u64 will happen after the mutliplication. Also,
> ppmdiff should be called pphundred_diff if you want to stick to this
> formula.
Maybe make a separate patch with all the pll limits fixes and we can yell
at the absppm diff computation here separately.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
