linux-kernel - Re: [PATCH v2] drm/amdgpu: add dce6 drm

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Message-ID: <CADnq5_O7njHcvu0ejvVPPKF7szsbEQ8oFfHr9GTyD+zAe2EJ8g@mail.gmail.com>
Date: Tue, 24 Sep 2024 10:02:35 -0400
From: Alex Deucher <alexdeucher@...il.com>
To: Jocelyn Falempe <jfalempe@...hat.com>
Cc: Lu Yao <yaolu@...inos.cn>, ckoenig.leichtzumerken@...il.com, daniel@...ll.ch, 
	Xinhui.Pan@....com, airlied@...il.com, alexander.deucher@....com, 
	amd-gfx@...ts.freedesktop.org, christian.koenig@....com, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	srinivasan.shanmugam@....com, sunil.khatri@....com
Subject: Re: [PATCH v2] drm/amdgpu: add dce6 drm_panic support

On Fri, Sep 20, 2024 at 11:36 AM Jocelyn Falempe <jfalempe@...hat.com> wrote:
>
> On 17/09/2024 15:21, Alex Deucher wrote:
> > On Mon, Aug 12, 2024 at 2:10 AM Lu Yao <yaolu@...inos.cn> wrote:
> >>
> >> Add support for the drm_panic module, which displays a pretty user
> >> friendly message on the screen when a Linux kernel panic occurs.
> >>
> >> Signed-off-by: Lu Yao <yaolu@...inos.cn>
> >
> > Patch looks good to me.  Any chance you want to convert the other
> > non-DC dce files (dce_v8_0.c, dce_v10_0.c, dce_v11_0.c) while you are
> > at it?
>
> I've made a similar patch in amdgpu_dm_plane.c, and it works on a Radeon
> pro w6400.
> But it only works when I'm in a VT terminal (so the framebuffer is
> linear and CPU accessible).
> When under Gnome/Wayland, the flag AMDGPU_GEM_CREATE_NO_CPU_ACCESS is
> set, so that means I can't vmap it ?

It just means that the application does not need CPU access.  Whether
or not the CPU can access the buffer or not depends on the size of the
PCI BAR.  E.g., if the driver or bios has resized the PCI BAR, then
the CPU can access the entire BAR, but if not you are generally
limited to the first 256M of framebuffer.

>
> Also I don't know if there is a similar way to disable
> tiling/compression on this hardware.

UNP_GRPH_CONTROL on chips with DCE display hardware and
DCSURF_ADDR_CONFIG and DCSURF_TILING_CONFIG on DCN display hardware.

Alex

>
> Best regards,
>
> --
>
> Jocelyn
>
>
> >
> > Alex
> >
> >
> >> ---
> >> Changes in v2:
> >> 1. Drop include "drm_internal.h"
> >> 2. Add disabling DC tiling ops.
> >> Per suggestion from previous thread:
> >> https://patchwork.freedesktop.org/patch/606879/?series=136832&rev=1
> >> ---
> >>   drivers/gpu/drm/amd/amdgpu/dce_v6_0.c | 48 +++++++++++++++++++++++++++
> >>   1 file changed, 48 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> >> index 05c0df97f01d..ba1b7a36caa3 100644
> >> --- a/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> >> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
> >> @@ -28,6 +28,7 @@
> >>   #include <drm/drm_modeset_helper.h>
> >>   #include <drm/drm_modeset_helper_vtables.h>
> >>   #include <drm/drm_vblank.h>
> >> +#include <drm/drm_panic.h>
> >>
> >>   #include "amdgpu.h"
> >>   #include "amdgpu_pm.h"
> >> @@ -2600,6 +2601,52 @@ static const struct drm_crtc_helper_funcs dce_v6_0_crtc_helper_funcs = {
> >>          .get_scanout_position = amdgpu_crtc_get_scanout_position,
> >>   };
> >>
> >> +static int dce_v6_0_drm_primary_plane_get_scanout_buffer(struct drm_plane *plane,
> >> +                                                        struct drm_scanout_buffer *sb)
> >> +{
> >> +       struct drm_framebuffer *fb;
> >> +       struct amdgpu_bo *abo;
> >> +       struct amdgpu_crtc *amdgpu_crtc;
> >> +       struct amdgpu_device *adev;
> >> +       uint32_t fb_format;
> >> +
> >> +       if (!plane->fb)
> >> +               return -EINVAL;
> >> +
> >> +       fb = plane->fb;
> >> +
> >> +       abo = gem_to_amdgpu_bo(fb->obj[0]);
> >> +       amdgpu_crtc = to_amdgpu_crtc(plane->crtc);
> >> +       adev = drm_to_adev(fb->dev);
> >> +
> >> +       if (!abo->kmap.virtual &&
> >> +           ttm_bo_kmap(&abo->tbo, 0, PFN_UP(abo->tbo.base.size), &abo->kmap)) {
> >> +               DRM_WARN("amdgpu bo map failed, panic won't be displayed\n");
> >> +               return -ENOMEM;
> >> +       }
> >> +
> >> +       if (abo->kmap.bo_kmap_type & TTM_BO_MAP_IOMEM_MASK)
> >> +               iosys_map_set_vaddr_iomem(&sb->map[0], abo->kmap.virtual);
> >> +       else
> >> +               iosys_map_set_vaddr(&sb->map[0], abo->kmap.virtual);
> >> +
> >> +       sb->width = fb->width;
> >> +       sb->height = fb->height;
> >> +       sb->format = fb->format;
> >> +       sb->pitch[0] = fb->pitches[0];
> >> +
> >> +       /* Disable DC tiling */
> >> +       fb_format = RREG32(mmGRPH_CONTROL + amdgpu_crtc->crtc_offset);
> >> +       fb_format &= ~GRPH_ARRAY_MODE(0x7);
> >> +       WREG32(mmGRPH_CONTROL + amdgpu_crtc->crtc_offset, fb_format);
> >> +
> >> +       return 0;
> >> +}
> >> +
> >> +static const struct drm_plane_helper_funcs dce_v6_0_drm_primary_plane_helper_funcs = {
> >> +       .get_scanout_buffer = dce_v6_0_drm_primary_plane_get_scanout_buffer
> >> +};
> >> +
> >>   static int dce_v6_0_crtc_init(struct amdgpu_device *adev, int index)
> >>   {
> >>          struct amdgpu_crtc *amdgpu_crtc;
> >> @@ -2627,6 +2674,7 @@ static int dce_v6_0_crtc_init(struct amdgpu_device *adev, int index)
> >>          amdgpu_crtc->encoder = NULL;
> >>          amdgpu_crtc->connector = NULL;
> >>          drm_crtc_helper_add(&amdgpu_crtc->base, &dce_v6_0_crtc_helper_funcs);
> >> +       drm_plane_helper_add(amdgpu_crtc->base.primary, &dce_v6_0_drm_primary_plane_helper_funcs);
> >>
> >>          return 0;
> >>   }
> >> --
> >> 2.25.1
> >>
> >
>