drm/i915: avoid big kmallocs on reading error state
Sometimes when user is trying to get error state out from
debugfs after gpu hang, the memory is low and/or fragmented
enough that kmalloc in seq_file will fail.
Prevent big kmalloc by avoiding seq_file and instead convert
error state to string in smaller chunks.
v2: better alloc flags, better truncate, correct
locking, and error handling improvements (Chris Wilson)
v3: printf annotations (Daniel Vetter)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 639ec0b..7772bb6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -826,6 +826,15 @@
u32 object_count;
};
+struct drm_i915_error_state_buf {
+ unsigned bytes;
+ unsigned size;
+ int err;
+ u8 *buf;
+ loff_t start;
+ loff_t pos;
+};
+
struct i915_gpu_error {
/* For hangcheck timer */
#define DRM_I915_HANGCHECK_PERIOD 1500 /* in ms */
@@ -1818,6 +1827,8 @@
/* i915_debugfs.c */
int i915_debugfs_init(struct drm_minor *minor);
void i915_debugfs_cleanup(struct drm_minor *minor);
+__printf(2, 3)
+void i915_error_printf(struct drm_i915_error_state_buf *e, const char *f, ...);
/* i915_suspend.c */
extern int i915_save_state(struct drm_device *dev);
@@ -1899,10 +1910,11 @@
/* overlay */
#ifdef CONFIG_DEBUG_FS
extern struct intel_overlay_error_state *intel_overlay_capture_error_state(struct drm_device *dev);
-extern void intel_overlay_print_error_state(struct seq_file *m, struct intel_overlay_error_state *error);
+extern void intel_overlay_print_error_state(struct drm_i915_error_state_buf *e,
+ struct intel_overlay_error_state *error);
extern struct intel_display_error_state *intel_display_capture_error_state(struct drm_device *dev);
-extern void intel_display_print_error_state(struct seq_file *m,
+extern void intel_display_print_error_state(struct drm_i915_error_state_buf *e,
struct drm_device *dev,
struct intel_display_error_state *error);
#endif