On Fri, Sep 02, 2022 at 01:47:14PM +0300, Jani Nikula wrote: > On Thu, 18 Aug 2022, Ville Syrjala <[email protected]> wrote: > > From: Ville Syrjälä <[email protected]> > > > > Validate the LFP data block a bit hardwer by making sure the > > fp_timing terminators (0xffff) are where we expect them to be. > > > > Signed-off-by: Ville Syrjälä <[email protected]> > > I wonder if it would be good to debug log at each of the "return false" > sites in fixup_lfp_data_ptrs() and validate_lfp_data_ptrs(). Anyway, > that's a separate change.
Not sure how much it would help. I suspect one still ends up decoding the whole hexdump by hand. > > Reviewed-by: Jani Nikula <[email protected]> > > > --- > > drivers/gpu/drm/i915/display/intel_bios.c | 60 ++++++++++++----------- > > 1 file changed, 32 insertions(+), 28 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c > > b/drivers/gpu/drm/i915/display/intel_bios.c > > index 198a2f4920cc..f1f861da9e93 100644 > > --- a/drivers/gpu/drm/i915/display/intel_bios.c > > +++ b/drivers/gpu/drm/i915/display/intel_bios.c > > @@ -135,18 +135,6 @@ static u32 raw_block_offset(const void *bdb, enum > > bdb_block_id section_id) > > return block - bdb; > > } > > > > -/* size of the block excluding the header */ > > -static u32 raw_block_size(const void *bdb, enum bdb_block_id section_id) > > -{ > > - const void *block; > > - > > - block = find_raw_section(bdb, section_id); > > - if (!block) > > - return 0; > > - > > - return get_blocksize(block); > > -} > > - > > struct bdb_block_entry { > > struct list_head node; > > enum bdb_block_id section_id; > > @@ -231,9 +219,14 @@ static bool validate_lfp_data_ptrs(const void *bdb, > > { > > int fp_timing_size, dvo_timing_size, panel_pnp_id_size, panel_name_size; > > int data_block_size, lfp_data_size; > > + const void *data_block; > > int i; > > > > - data_block_size = raw_block_size(bdb, BDB_LVDS_LFP_DATA); > > + data_block = find_raw_section(bdb, BDB_LVDS_LFP_DATA); > > + if (!data_block) > > + return false; > > + > > + data_block_size = get_blocksize(data_block); > > if (data_block_size == 0) > > return false; > > > > @@ -261,21 +254,6 @@ static bool validate_lfp_data_ptrs(const void *bdb, > > if (16 * lfp_data_size > data_block_size) > > return false; > > > > - /* > > - * Except for vlv/chv machines all real VBTs seem to have 6 > > - * unaccounted bytes in the fp_timing table. And it doesn't > > - * appear to be a really intentional hole as the fp_timing > > - * 0xffff terminator is always within those 6 missing bytes. > > - */ > > - if (fp_timing_size + dvo_timing_size + panel_pnp_id_size != > > lfp_data_size && > > - fp_timing_size + 6 + dvo_timing_size + panel_pnp_id_size != > > lfp_data_size) > > - return false; > > - > > - if (ptrs->ptr[0].fp_timing.offset + fp_timing_size > > > ptrs->ptr[0].dvo_timing.offset || > > - ptrs->ptr[0].dvo_timing.offset + dvo_timing_size != > > ptrs->ptr[0].panel_pnp_id.offset || > > - ptrs->ptr[0].panel_pnp_id.offset + panel_pnp_id_size != > > lfp_data_size) > > - return false; > > - > > /* make sure the table entries have uniform size */ > > for (i = 1; i < 16; i++) { > > if (ptrs->ptr[i].fp_timing.table_size != fp_timing_size || > > @@ -289,6 +267,23 @@ static bool validate_lfp_data_ptrs(const void *bdb, > > return false; > > } > > > > + /* > > + * Except for vlv/chv machines all real VBTs seem to have 6 > > + * unaccounted bytes in the fp_timing table. And it doesn't > > + * appear to be a really intentional hole as the fp_timing > > + * 0xffff terminator is always within those 6 missing bytes. > > + */ > > + if (fp_timing_size + 6 + dvo_timing_size + panel_pnp_id_size == > > lfp_data_size) > > + fp_timing_size += 6; > > + > > + if (fp_timing_size + dvo_timing_size + panel_pnp_id_size != > > lfp_data_size) > > + return false; > > + > > + if (ptrs->ptr[0].fp_timing.offset + fp_timing_size != > > ptrs->ptr[0].dvo_timing.offset || > > + ptrs->ptr[0].dvo_timing.offset + dvo_timing_size != > > ptrs->ptr[0].panel_pnp_id.offset || > > + ptrs->ptr[0].panel_pnp_id.offset + panel_pnp_id_size != > > lfp_data_size) > > + return false; > > + > > /* make sure the tables fit inside the data block */ > > for (i = 0; i < 16; i++) { > > if (ptrs->ptr[i].fp_timing.offset + fp_timing_size > > > data_block_size || > > @@ -300,6 +295,15 @@ static bool validate_lfp_data_ptrs(const void *bdb, > > if (ptrs->panel_name.offset + 16 * panel_name_size > data_block_size) > > return false; > > > > + /* make sure fp_timing terminators are present at expected locations */ > > + for (i = 0; i < 16; i++) { > > + const u16 *t = data_block + ptrs->ptr[i].fp_timing.offset + > > + fp_timing_size - 2; > > + > > + if (*t != 0xffff) > > + return false; > > + } > > + > > return true; > > } > > -- > Jani Nikula, Intel Open Source Graphics Center -- Ville Syrjälä Intel
