On Mon, Jul 15, 2024 at 02:26:59AM GMT, Uma Shankar wrote:
As per recommendation in the workarounds:
WA_22019338487

There is an issue with accessing Stolen memory pages due a
hardware limitation. Limit the usage of stolen memory for
fbdev for LNL+. Don't use BIOS FB from stolen on LNL+ and
assign the same from system memory.

v2: Corrected the WA Number, limited WA to LNL and
   Adopted XE_WA framework as suggested by Lucas and Matt.

Signed-off-by: Uma Shankar <uma.shan...@intel.com>
---
drivers/gpu/drm/xe/display/intel_fbdev_fb.c   | 20 ++++++++++++++++++-
drivers/gpu/drm/xe/display/xe_plane_initial.c | 12 +++++++++++
drivers/gpu/drm/xe/xe_wa_oob.rules            |  1 +
3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/display/intel_fbdev_fb.c 
b/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
index 816ad13821a8..9c70c9158108 100644
--- a/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
+++ b/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
@@ -10,6 +10,8 @@
#include "xe_bo.h"
#include "xe_gt.h"
#include "xe_ttm_stolen_mgr.h"
+#include "xe_wa.h"

missing newline

+#include <generated/xe_wa_oob.h>

struct intel_framebuffer *intel_fbdev_fb_alloc(struct drm_fb_helper *helper,
                                               struct 
drm_fb_helper_surface_size *sizes)
@@ -20,6 +22,9 @@ struct intel_framebuffer *intel_fbdev_fb_alloc(struct 
drm_fb_helper *helper,
        struct drm_mode_fb_cmd2 mode_cmd = {};
        struct drm_i915_gem_object *obj;
        int size;
+       bool wa_22019338487 = false;
+       struct xe_gt *gt;
+       u8 id;

        /* we don't do packed 24bpp */
        if (sizes->surface_bpp == 24)
@@ -37,7 +42,19 @@ struct intel_framebuffer *intel_fbdev_fb_alloc(struct 
drm_fb_helper *helper,
        size = PAGE_ALIGN(size);
        obj = ERR_PTR(-ENODEV);

-       if (!IS_DGFX(xe)) {
+       /*
+        * WA_22019338487:
+        * There is an issue with accessing Stolen memory pages
+        * due a hardware limitation. Limit the usage of stolen
+        * memory for fbdev for LNL+. Don't use BIOS FB from
+        * stolen on LNL+ and assign the same from system memory
+        */
+       for_each_gt(gt, xe, id) {

why do you loop here, but in the other path you use main_gt of tile0?

I think at this point it's pretty safe to just do:

        if (XE_WA(xe_root_mmio_gt(xe), 22019338487))

Also, no need for the comment above, the commit message and WA
documentation is sufficient.

+               if (XE_WA(gt, 22019338487))
+                       wa_22019338487 = true;
+       }
+
+       if (!IS_DGFX(xe) && !wa_22019338487) {
                obj = xe_bo_create_pin_map(xe, xe_device_get_root_tile(xe),
                                           NULL, size,
                                           ttm_bo_type_kernel, 
XE_BO_FLAG_SCANOUT |
@@ -48,6 +65,7 @@ struct intel_framebuffer *intel_fbdev_fb_alloc(struct 
drm_fb_helper *helper,
                else
                        drm_info(&xe->drm, "Allocated fbdev into stolen failed: 
%li\n", PTR_ERR(obj));
        }
+
        if (IS_ERR(obj)) {
                obj = xe_bo_create_pin_map(xe, xe_device_get_root_tile(xe), 
NULL, size,
                                           ttm_bo_type_kernel, 
XE_BO_FLAG_SCANOUT |
diff --git a/drivers/gpu/drm/xe/display/xe_plane_initial.c 
b/drivers/gpu/drm/xe/display/xe_plane_initial.c
index 5eccd6abb3ef..7e93ddad6df8 100644
--- a/drivers/gpu/drm/xe/display/xe_plane_initial.c
+++ b/drivers/gpu/drm/xe/display/xe_plane_initial.c
@@ -18,6 +18,8 @@
#include "intel_frontbuffer.h"
#include "intel_plane_initial.h"
#include "xe_bo.h"
+#include "xe_wa.h"
+#include <generated/xe_wa_oob.h>

static bool
intel_reuse_initial_plane_obj(struct intel_crtc *this,
@@ -104,6 +106,16 @@ initial_plane_bo(struct xe_device *xe,
                phys_base = base;
                flags |= XE_BO_FLAG_STOLEN;

+               /*
+                * WA_22019338487:
+                * There is an issue with accessing Stolen memory pages
+                * due a hardware limitation. Limit the usage of stolen
+                * memory for fbdev for LNL+. Don't use BIOS FB from
+                * stolen on LNL+ and assign the same from system memory
+                */
+               if (XE_WA(tile0->primary_gt, 22019338487))

just use the same xe_root_mmio_gt() as suggested above.

+                       return NULL;
+
                /*
                 * If the FB is too big, just don't use it since fbdev is not 
very
                 * important and we should probably use that space with FBC or 
other
diff --git a/drivers/gpu/drm/xe/xe_wa_oob.rules 
b/drivers/gpu/drm/xe/xe_wa_oob.rules
index 08f7336881e3..9b08fedbf85c 100644
--- a/drivers/gpu/drm/xe/xe_wa_oob.rules
+++ b/drivers/gpu/drm/xe/xe_wa_oob.rules
@@ -29,4 +29,5 @@
13011645652     GRAPHICS_VERSION(2004)
22019338487     MEDIA_VERSION(2000)
                GRAPHICS_VERSION(2001)
+               GRAPHICS_VERSION(2004)

This will end up matching the graphics GT in LNL for other paths it was
not previously taking. Looking at the code, main change will be:

drivers/gpu/drm/xe/xe_guc_pc.c:pc_max_freq_cap()
drivers/gpu/drm/xe/xe_gt.c:xe_gt_sanitize_freq()

about the freq handling for the GT. And the change will be wrong

I think we could just make this a new entry with:

        22019338487_display GRAPHICS_VERSION(2024)
or
        22019338487_display PLATFORM(LUNARLAKE)

I like the second more as then it doesn't matter what gt you use in the
code. Matt Roper, thoughts?

Lucas De Marchi

16023588340     GRAPHICS_VERSION(2001)
--
2.42.0

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