On Tue, 16 Jun 2026, Mitul Golani <[email protected]> wrote:
> Add a per-CRTC debugfs entry 'vrr/cmrr' and a debugfs file
> (numerator/denominator) that indicates user intended target
> refresh rate and video mode requirement.
>
> Signed-off-by: Mitul Golani <[email protected]>
> ---
> .../drm/i915/display/intel_display_debugfs.c | 2 +
> .../drm/i915/display/intel_display_types.h | 5 +
> drivers/gpu/drm/i915/display/intel_vrr.c | 105 ++++++++++++++++++
> drivers/gpu/drm/i915/display/intel_vrr.h | 2 +
> 4 files changed, 114 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index 08004c1ba03f..1ce6e73ec83c 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -48,6 +48,7 @@
> #include "intel_psr.h"
> #include "intel_psr_regs.h"
> #include "intel_vdsc.h"
> +#include "intel_vrr.h"
> #include "intel_wm.h"
> #include "intel_tc.h"
>
> @@ -1393,6 +1394,7 @@ void intel_crtc_debugfs_add(struct intel_crtc *crtc)
> intel_drrs_crtc_debugfs_add(crtc);
> intel_fbc_crtc_debugfs_add(crtc);
> hsw_ips_crtc_debugfs_add(crtc);
> + intel_vrr_crtc_debugfs_add(crtc);
>
> debugfs_create_file("i915_current_bpc", 0444, root, crtc,
> &i915_current_bpc_fops);
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 6cd102a3b610..897a1ffd7b79 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1545,6 +1545,11 @@ struct intel_crtc {
> +
> + if (*numerator == 0)
> + return -EINVAL;
> +
> + if (*denominator != 1000 && *denominator != 1001)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +static int intel_vrr_cmrr_show(struct seq_file *m, void *data)
> +{
> + struct intel_crtc *crtc = m->private;
> +
> + seq_printf(m, "%u/%u\n", crtc->cmrr.numerator, crtc->cmrr.denominator);
> +
> + return 0;
> +}
> +
> +static int intel_vrr_cmrr_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, intel_vrr_cmrr_show, inode->i_private);
> +}
> +
> +static ssize_t intel_vrr_cmrr_write(struct file *file, const char __user
> *ubuf,
> + size_t len, loff_t *offp)
> +{
> + struct seq_file *m = file->private_data;
> + struct intel_crtc *crtc = m->private;
> + u32 numerator, denominator;
> + char kbuf[32];
> + int ret;
> +
> + if (len >= sizeof(kbuf))
> + return -EINVAL;
> +
> + if (copy_from_user(kbuf, ubuf, len))
> + return -EFAULT;
> +
> + kbuf[len] = '\0';
> +
> + ret = cmrr_parse_ratio(kbuf, &numerator, &denominator);
> + if (ret)
> + return ret;
> +
> + crtc->cmrr.numerator = numerator;
> + crtc->cmrr.denominator = denominator;
> +
> + return len;
> +}
> +
> +static const struct file_operations intel_vrr_cmrr_fops = {
> + .owner = THIS_MODULE,
> + .open = intel_vrr_cmrr_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = single_release,
> + .write = intel_vrr_cmrr_write,
> +};
> +
> +void intel_vrr_crtc_debugfs_add(struct intel_crtc *crtc)
> +{
> + struct intel_display *display = to_intel_display(crtc);
> + struct dentry *vrr_dir;
> +
> + if (!HAS_VRR(display))
> + return;
> +
> + vrr_dir = debugfs_create_dir("vrr", crtc->base.debugfs_entry);
Please give rationale for adding a directory.
Driver specific debugfs files should have a prefix. Using just "vrr"
blocks using it as a generic drm debugfs file. Please let's use "intel_"
going forward (instead of "i915_" that we've had before xe).
> +
> + if (HAS_CMRR(display))
> + debugfs_create_file("cmrr", 0600, vrr_dir, crtc,
> + &intel_vrr_cmrr_fops);
> +}
> +
> diff --git a/drivers/gpu/drm/i915/display/intel_vrr.h
> b/drivers/gpu/drm/i915/display/intel_vrr.h
> index 55e9c429f579..19c7990be1b2 100644
> --- a/drivers/gpu/drm/i915/display/intel_vrr.h
> +++ b/drivers/gpu/drm/i915/display/intel_vrr.h
> @@ -56,4 +56,6 @@ int intel_vrr_dcb_vmax_vblank_start_next(const struct
> intel_crtc_state *crtc_sta
> int intel_vrr_dcb_vmin_vblank_start_final(const struct intel_crtc_state
> *crtc_state);
> int intel_vrr_dcb_vmax_vblank_start_final(const struct intel_crtc_state
> *crtc_state);
>
> +void intel_vrr_crtc_debugfs_add(struct intel_crtc *crtc);
> +
> #endif /* __INTEL_VRR_H__ */
--
Jani Nikula, Intel
