Hi Mitul,
On Mon, Jun 10, 2024 at 12:52:02PM +0530, Mitul Golani wrote:
...
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c
> b/drivers/gpu/drm/i915/display/intel_vrr.c
> index 4ad99a54aa83..05f67dc9d98d 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.c
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.c
> @@ -12,6 +12,9 @@
> #include "intel_vrr_regs.h"
> #include "intel_dp.h"
>
> +#define FIXED_POINT_PRECISION 100
> +#define CMRR_PRECISION_TOLERANCE 10
> +
> bool intel_vrr_is_capable(struct intel_connector *connector)
> {
> const struct drm_display_info *info = &connector->base.display_info;
> @@ -107,6 +110,52 @@ int intel_vrr_vmax_vblank_start(const struct
> intel_crtc_state *crtc_state)
> return crtc_state->vrr.vmax - intel_vrr_vblank_exit_length(crtc_state);
> }
>
> +static bool
> +is_cmrr_frac_required(struct intel_crtc_state *crtc_state)
> +{
> + int calculated_refresh_k, actual_refresh_k, pixel_clock_per_line;
> + struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
> + struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> +
> + if (!HAS_CMRR(i915))
> + return false;
> +
> + actual_refresh_k =
> + drm_mode_vrefresh(adjusted_mode) * FIXED_POINT_PRECISION;
> + pixel_clock_per_line =
> + adjusted_mode->crtc_clock * 1000 / adjusted_mode->crtc_htotal;
> + calculated_refresh_k =
> + pixel_clock_per_line * FIXED_POINT_PRECISION /
> adjusted_mode->crtc_vtotal;
> +
> + if ((actual_refresh_k - calculated_refresh_k) <
> CMRR_PRECISION_TOLERANCE)
> + return false;
> +
> + return true;
> +}
> +
> +static unsigned int
> +cmrr_get_vtotal(struct intel_crtc_state *crtc_state, bool
> video_mode_required)
> +{
> + int multiplier_m = 1, multiplier_n = 1, vtotal, desired_refresh_rate;
> + long long adjusted_pixel_rate;
> + struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
> +
> + desired_refresh_rate = drm_mode_vrefresh(adjusted_mode);
> +
> + if (video_mode_required) {
> + multiplier_m = 1001;
> + multiplier_n = 1000;
> + }
> +
> + crtc_state->cmrr.cmrr_n =
> + desired_refresh_rate * adjusted_mode->crtc_htotal *
> multiplier_n;
> + vtotal = (adjusted_mode->crtc_clock * 1000 * multiplier_n) /
> crtc_state->cmrr.cmrr_n;
> + adjusted_pixel_rate = adjusted_mode->crtc_clock * 1000 * multiplier_m;
> + crtc_state->cmrr.cmrr_m = do_div(adjusted_pixel_rate,
> crtc_state->cmrr.cmrr_n);
> +
> + return vtotal;
> +}
This change is now in -next as commit 1676ecd303ac ("drm/i915: Compute
CMRR and calculate vtotal"), where it breaks the xe build for 32-bit
platforms with:
$ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- allmodconfig
drivers/gpu/drm/xe/i915-display/intel_vrr.o
In file included from arch/arm/include/asm/div64.h:107,
from include/linux/math.h:6,
from include/linux/kernel.h:27,
from include/linux/cpumask.h:11,
from include/linux/smp.h:13,
from include/linux/lockdep.h:14,
from include/linux/spinlock.h:63,
from include/linux/kref.h:16,
from include/drm/drm_device.h:5,
from include/drm/drm_drv.h:35,
from drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h:13,
from drivers/gpu/drm/i915/display/intel_vrr.c:7:
drivers/gpu/drm/i915/display/intel_vrr.c: In function 'cmrr_get_vtotal':
include/asm-generic/div64.h:222:35: error: comparison of distinct pointer
types lacks a cast [-Werror]
222 | (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
| ^~
drivers/gpu/drm/i915/display/intel_vrr.c:155:35: note: in expansion of macro
'do_div'
155 | crtc_state->cmrr.cmrr_m = do_div(adjusted_pixel_rate,
crtc_state->cmrr.cmrr_n);
| ^~~~~~
cc1: all warnings being treated as errors
Also, is do_div() correct here? It is different from the other div_()
macros in that the "return value" is the remainder, not the result of
the division.
Cheers,
Nathan
