On 2018-02-27 05:34 AM, Michel Dänzer wrote: > On 2018-02-26 09:15 PM, Harry Wentland wrote: >> From: "Leo (Sunpeng) Li" <sunpeng.li at amd.com> >> >> Non-legacy LUT size should reflect hw capability. Change size from 256 >> to 4096. >> >> However, X doesn't seem to play with legacy LUTs of such size. >> Therefore, check for legacy lut when updating DC states, and update >> accordingly. >> >> v2: Use a macro for the maximum drm LUT value. >> >> Signed-off-by: Leo (Sunpeng) Li <sunpeng.li at amd.com> >> Reviewed-by: Harry Wentland <Harry.Wentland at amd.com> >> --- >> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +- >> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 4 +- >> .../drm/amd/display/amdgpu_dm/amdgpu_dm_color.c | 77 ++++++++++++++++------ >> 3 files changed, 61 insertions(+), 22 deletions(-) >> >> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >> index bb9405daa087..f782518fc424 100644 >> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c >> @@ -3228,7 +3228,7 @@ static int amdgpu_dm_crtc_init(struct amdgpu_display_manager *dm, >> dm->adev->mode_info.crtcs[crtc_index] = acrtc; >> drm_crtc_enable_color_mgmt(&acrtc->base, MAX_COLOR_LUT_ENTRIES, >> true, MAX_COLOR_LUT_ENTRIES); >> - drm_mode_crtc_set_gamma_size(&acrtc->base, MAX_COLOR_LUT_ENTRIES); >> + drm_mode_crtc_set_gamma_size(&acrtc->base, MAX_COLOR_LEGACY_LUT_ENTRIES); > > This means userspace can't set gamma ramps with more than 256 entries, > since drm_mode_gamma_set_ioctl returns an error if the sizes don't > match. We should just fix userspace which tries to use the wrong size. It seems X hard-codes 256 entries for the legacy lut, ignoring what the kernel requests: xf86CrtcCreate in xserver/hw/xfree86/modes/xf86Crtc.c (~line 120): /* Preallocate gamma at a sensible size. */ crtc->gamma_size = 256; I confirmed this as well via a printk on the user LUT size in drm_mode_gamma_set_ioctl (after reverting to 4096 gamma size, of course). I'm not sure if modifying that line in X will be straightforward. It's worth noting that drm_mode_crtc_set_gamma_size() only sets the legacy gamma size. Non-legacy gamma (de/regamma) sizes are reported via a mode property, and does not conflict with legacy size. Therefore, reporting a different size for legacy shouldn't be an issue, AFAIK; as long as we check the DRM lut size and update DC accordingly, which we're doing. Leo > >
