Re: [PATCH 08/14] drm/imx: dc: Use TCON operation mode
From: Frank Li <Frank.li@nxp.com>
Date: 2025-09-19 15:24:13
Also in:
dri-devel, imx, linux-arm-kernel, lkml
On Fri, Jul 04, 2025 at 05:03:55PM +0800, Liu Ying wrote:
In TCON operation mode, sync signals from FrameGen are ignored, but a much more customized output timing can be generated by the TCON module. By using TCON operaton mode, generate KACHUNK signal along with HSYNC/VSYNC/data enable signals. The KACHUNK signal is used as a synchronization signal inside the prefetch engine(DPRC + PRG(s), attached to FetchUnit(s)). Carefully switch TCON bypass mode to TCON operation mode when CRTC is being enabled so that the prefetch engine may evade the first dumb frame generated by the display controller. Since TCON BYPASS bit is controlled by KMS driver when doing atomic commits, drop the bit setting when initializing TCON. This also avoids accidentally initializing TCON BYPASS bit to 1 when driver module removing and re-installing where an upcoming patch would disable a CRTC at boot in TCON operation mode if needed. Signed-off-by: Liu Ying <victor.liu@nxp.com> --- drivers/gpu/drm/imx/dc/dc-crtc.c | 28 ++++++++++ drivers/gpu/drm/imx/dc/dc-de.h | 2 + drivers/gpu/drm/imx/dc/dc-kms.h | 2 + drivers/gpu/drm/imx/dc/dc-tc.c | 114 +++++++++++++++++++++++++++++++++++++-- 4 files changed, 142 insertions(+), 4 deletions(-)
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quoted hunk ↗ jump to hunk
@@ -249,6 +260,7 @@ dc_crtc_atomic_enable(struct drm_crtc *crtc, struct drm_atomic_state *state) enable_irq(dc_crtc->irq_ed_safe_shdload); dc_fg_cfg_videomode(dc_crtc->fg, adj); + dc_tc_cfg_videomode(dc_crtc->tc, adj); dc_cf_framedimensions(dc_crtc->cf_cont, adj->crtc_hdisplay, adj->crtc_vdisplay);@@ -273,7 +285,22 @@ dc_crtc_atomic_enable(struct drm_crtc *crtc, struct drm_atomic_state *state) dc_ed_pec_sync_trigger(dc_crtc->ed_cont); dc_ed_pec_sync_trigger(dc_crtc->ed_safe); dc_fg_shdtokgen(dc_crtc->fg); + + /* Don't relinquish CPU until TCON is set to operation mode. */ + local_irq_save(flags); + preempt_disable(); + dc_fg_enable(dc_crtc->fg); + /* + * Turn TCON into operation mode as soon as the first dumb + * frame is generated by DC(we don't relinquish CPU to ensure + * this). This makes DPR/PRG be able to evade the frame. + */ + DC_CRTC_WAIT_FOR_FRAMEGEN_FRAME_INDEX_MOVING(dc_crtc->fg); + dc_tc_set_operation_mode(dc_crtc->tc); + + local_irq_restore(flags); + preempt_enable();
Does it need reverised order?
quoted hunk ↗ jump to hunk
DC_CRTC_WAIT_FOR_COMPLETION_TIMEOUT(ed_safe_shdload_done); DC_CRTC_WAIT_FOR_COMPLETION_TIMEOUT(ed_cont_shdload_done);@@ -561,6 +588,7 @@ int dc_crtc_init(struct dc_drm_device *dc_drm, int crtc_index) dc_crtc->ed_cont = pe->ed_cont[crtc_index]; dc_crtc->ed_safe = pe->ed_safe[crtc_index]; dc_crtc->fg = de->fg; + dc_crtc->tc = de->tc; dc_crtc->irq_dec_framecomplete = de->irq_framecomplete; dc_crtc->irq_dec_seqcomplete = de->irq_seqcomplete;diff --git a/drivers/gpu/drm/imx/dc/dc-de.h b/drivers/gpu/drm/imx/dc/dc-de.h index 211f3fcc1a9ad642617d3b22e35ea923f75e645b..c39f2ef5eea98c3eb6ae9b5392f9bf9f7e33e7c5 100644 --- a/drivers/gpu/drm/imx/dc/dc-de.h +++ b/drivers/gpu/drm/imx/dc/dc-de.h@@ -54,6 +54,8 @@ enum drm_mode_status dc_fg_check_clock(struct dc_fg *fg, int clk_khz); void dc_fg_init(struct dc_fg *fg);
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-- 2.34.1