diff options
Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_link_bw.c')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_link_bw.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_link_bw.c b/drivers/gpu/drm/i915/display/intel_link_bw.c new file mode 100644 index 000000000000..ed63e7a9d859 --- /dev/null +++ b/drivers/gpu/drm/i915/display/intel_link_bw.c @@ -0,0 +1,205 @@ +// SPDX-License-Identifier: MIT +/* + * Copyright © 2023 Intel Corporation + */ + +#include "i915_drv.h" + +#include "intel_atomic.h" +#include "intel_display_types.h" +#include "intel_link_bw.h" + +/** + * intel_link_bw_init_limits - initialize BW limits + * @i915: device instance + * @limits: link BW limits + * + * Initialize @limits. + */ +void intel_link_bw_init_limits(struct drm_i915_private *i915, struct intel_link_bw_limits *limits) +{ + enum pipe pipe; + + limits->bpp_limit_reached_pipes = 0; + for_each_pipe(i915, pipe) + limits->max_bpp_x16[pipe] = INT_MAX; +} + +/** + * intel_link_bw_reduce_bpp - reduce maximum link bpp for a selected pipe + * @state: atomic state + * @limits: link BW limits + * @pipe_mask: mask of pipes to select from + * @reason: explanation of why bpp reduction is needed + * + * Select the pipe from @pipe_mask with the biggest link bpp value and set the + * maximum of link bpp in @limits below this value. Modeset the selected pipe, + * so that its state will get recomputed. + * + * This function can be called to resolve a link's BW overallocation by reducing + * the link bpp of one pipe on the link and hence reducing the total link BW. + * + * Returns + * - 0 in case of success + * - %-ENOSPC if no pipe can further reduce its link bpp + * - Other negative error, if modesetting the selected pipe failed + */ +int intel_link_bw_reduce_bpp(struct intel_atomic_state *state, + struct intel_link_bw_limits *limits, + u8 pipe_mask, + const char *reason) +{ + struct drm_i915_private *i915 = to_i915(state->base.dev); + enum pipe max_bpp_pipe = INVALID_PIPE; + struct intel_crtc *crtc; + int max_bpp = 0; + + for_each_intel_crtc_in_pipe_mask(&i915->drm, crtc, pipe_mask) { + struct intel_crtc_state *crtc_state; + int link_bpp; + + if (limits->bpp_limit_reached_pipes & BIT(crtc->pipe)) + continue; + + crtc_state = intel_atomic_get_crtc_state(&state->base, + crtc); + if (IS_ERR(crtc_state)) + return PTR_ERR(crtc_state); + + if (crtc_state->dsc.compression_enable) + link_bpp = crtc_state->dsc.compressed_bpp; + else + /* + * TODO: for YUV420 the actual link bpp is only half + * of the pipe bpp value. The MST encoder's BW allocation + * is based on the pipe bpp value, set the actual link bpp + * limit here once the MST BW allocation is fixed. + */ + link_bpp = crtc_state->pipe_bpp; + + if (link_bpp > max_bpp) { + max_bpp = link_bpp; + max_bpp_pipe = crtc->pipe; + } + } + + if (max_bpp_pipe == INVALID_PIPE) + return -ENOSPC; + + limits->max_bpp_x16[max_bpp_pipe] = to_bpp_x16(max_bpp) - 1; + + return intel_modeset_pipes_in_mask_early(state, reason, + BIT(max_bpp_pipe)); +} + +/** + * intel_link_bw_set_bpp_limit_for_pipe - set link bpp limit for a pipe to its minimum + * @state: atomic state + * @old_limits: link BW limits + * @new_limits: link BW limits + * @pipe: pipe + * + * Set the link bpp limit for @pipe in @new_limits to its value in + * @old_limits and mark this limit as the minimum. This function must be + * called after a pipe's compute config function failed, @old_limits + * containing the bpp limit with which compute config previously passed. + * + * The function will fail if setting a minimum is not possible, either + * because the old and new limits match (and so would lead to a pipe compute + * config failure) or the limit is already at the minimum. + * + * Returns %true in case of success. + */ +bool +intel_link_bw_set_bpp_limit_for_pipe(struct intel_atomic_state *state, + const struct intel_link_bw_limits *old_limits, + struct intel_link_bw_limits *new_limits, + enum pipe pipe) +{ + struct drm_i915_private *i915 = to_i915(state->base.dev); + + if (pipe == INVALID_PIPE) + return false; + + if (new_limits->max_bpp_x16[pipe] == + old_limits->max_bpp_x16[pipe]) + return false; + + if (drm_WARN_ON(&i915->drm, + new_limits->bpp_limit_reached_pipes & BIT(pipe))) + return false; + + new_limits->max_bpp_x16[pipe] = + old_limits->max_bpp_x16[pipe]; + new_limits->bpp_limit_reached_pipes |= BIT(pipe); + + return true; +} + +static int check_all_link_config(struct intel_atomic_state *state, + struct intel_link_bw_limits *limits) +{ + /* TODO: Check all shared display link configurations like FDI */ + return 0; +} + +static bool +assert_link_limit_change_valid(struct drm_i915_private *i915, + const struct intel_link_bw_limits *old_limits, + const struct intel_link_bw_limits *new_limits) +{ + bool bpps_changed = false; + enum pipe pipe; + + for_each_pipe(i915, pipe) { + /* The bpp limit can only decrease. */ + if (drm_WARN_ON(&i915->drm, + new_limits->max_bpp_x16[pipe] > + old_limits->max_bpp_x16[pipe])) + return false; + + if (new_limits->max_bpp_x16[pipe] < + old_limits->max_bpp_x16[pipe]) + bpps_changed = true; + } + + /* At least one limit must change. */ + if (drm_WARN_ON(&i915->drm, + !bpps_changed)) + return false; + + return true; +} + +/** + * intel_link_bw_atomic_check - check display link states and set a fallback config if needed + * @state: atomic state + * @new_limits: link BW limits + * + * Check the configuration of all shared display links in @state and set new BW + * limits in @new_limits if there is a BW limitation. + * + * Returns: + * - 0 if the confugration is valid + * - %-EAGAIN, if the configuration is invalid and @new_limits got updated + * with fallback values with which the configuration of all CRTCs + * in @state must be recomputed + * - Other negative error, if the configuration is invalid without a + * fallback possibility, or the check failed for another reason + */ +int intel_link_bw_atomic_check(struct intel_atomic_state *state, + struct intel_link_bw_limits *new_limits) +{ + struct drm_i915_private *i915 = to_i915(state->base.dev); + struct intel_link_bw_limits old_limits = *new_limits; + int ret; + + ret = check_all_link_config(state, new_limits); + if (ret != -EAGAIN) + return ret; + + if (!assert_link_limit_change_valid(i915, &old_limits, new_limits)) + return -EINVAL; + + return -EAGAIN; +} |