On Mon, 29 Aug 2022, Ville Syrjala ville.syrjala@linux.intel.com wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
Turns out the MIPI sequence block version number and new block size fields are considered part of the block header and are not included in the reported new block size field itself. Bump up the block size appropriately so that we'll copy over the last five bytes of the block as well.
For this particular machine those last five bytes included parts of the GPIO op for the backlight on sequence, causing the backlight no longer to turn back on:
Sequence 6 - MIPI_SEQ_BACKLIGHT_ON Delay: 20000 us
GPIO index 0, number 0, set 0 (0x00)
GPIO index 1, number 70, set 1 (0x01)Cc: stable@vger.kernel.org Fixes: e163cfb4c96d ("drm/i915/bios: Make copies of VBT data blocks") Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6652 Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
drivers/gpu/drm/i915/display/intel_bios.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c index 81d6cfbd2615..d493d04f4049 100644 --- a/drivers/gpu/drm/i915/display/intel_bios.c +++ b/drivers/gpu/drm/i915/display/intel_bios.c @@ -479,6 +479,13 @@ init_bdb_block(struct drm_i915_private *i915, block_size = get_blocksize(block);
- /*
* Version number and new block size are considered* part of the header for MIPI sequenece block v3+.*/
Quoth Bspec, "This field specifies the size of this entire data structure excluding this header." Okay.
- if (section_id == BDB_MIPI_SEQUENCE && *(const u8 *)block >= 3)
block_size += 5;
Since we need to look at the header later, we can't just use data + 5. Okay.
Reviewed-by: Jani Nikula jani.nikula@intel.com
I just don't get the whole sequence block u32 size thing, because the vbt header and bdb header still have u16, and they're supposed to cover the entire vbt and all bdb data blocks. And this is what we check anyway.
entry = kzalloc(struct_size(entry, data, max(min_size, block_size) + 3), GFP_KERNEL); if (!entry) {