GT VEBOX DISABLE is only 4 bits wide but it was using a 8 bits wide mask, the remaning reserved bits is set to 0 causing 4 more nonexistent VEBOX engines being detected as enabled, triggering the BUG_ON() because of mismatch between vebox_mask and newly added VEBOX_MASK(). [ 64.081621] [drm:intel_device_info_init_mmio [i915]] vdbox enable: 0005, instances: 0005 [ 64.081763] [drm:intel_device_info_init_mmio [i915]] vebox enable: 00f1, instances: 0001 [ 64.081825] intel_device_info_init_mmio:925 GEM_BUG_ON(vebox_mask != ({ unsigned int first__ = (VECS0); unsigned int count__ = (2); ((&(dev_priv)->__info)->engine_mask & (((~0UL) - (1UL << (first__)) + 1) & (~0UL >> (64 - 1 - (first__ + count__ - 1))))) >> first__; })) [ 64.082047] ------------[ cut here ]------------ [ 64.082054] kernel BUG at drivers/gpu/drm/i915/intel_device_info.c:925! BSpec: 20680 Fixes: 26376a7e74d2 ("drm/i915/icl: Check for fused-off VDBOX and VEBOX instances") Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Oscar Mateo <oscar.mateo@intel.com> Signed-off-by: José Roberto de Souza <jose.souza@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20190326230223.26336-1-jose.souza@intel.com (cherry picked from commit 547fcf9b1c608cf5c43c156a8773a94c6a38dc44) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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