From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3DEECC433EF for ; Tue, 12 Apr 2022 08:19:07 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CBFA510E4B6; Tue, 12 Apr 2022 08:19:06 +0000 (UTC) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7136010E4B6 for ; Tue, 12 Apr 2022 08:19:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1649751545; x=1681287545; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=vgt6PVaOIiSYPVGo9wcT+11aoppS8L9DUPUCTR+HegE=; b=gkMCbtxfcwXCgbhryr/RhuPXhcuTNUZZ5KA1X2XFJ6mlaNSb0BX6iNp/ BE1SzKEJHLObxwOuh4nrn5txd3mX/984V7MBcRRS+9O898wrjmujbqwbv IxL6+sX6tF4XPmQAaI+1AMuCyhtO+f+Ln6vlXkoJHz2xZT9iTPTIzkFl5 XHuz9sHgfoolFAZ25M9gYrhoaeRaEWKeflolzP4EVZu5Zn/YTflwXFokw sKMcve0b70vS08ZQRrRmxP62FJWeXveJozZIS672GdRVHG2gSS6k+/+cw +aMrVtuDV3nvtxl7r+z+5Dct0sFoajPZvryHmzBOBwMp3KSINd4YL1BDP g==; X-IronPort-AV: E=McAfee;i="6400,9594,10314"; a="348752541" X-IronPort-AV: E=Sophos;i="5.90,253,1643702400"; d="scan'208";a="348752541" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2022 01:19:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,253,1643702400"; d="scan'208";a="655007128" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.51]) by fmsmga002.fm.intel.com with SMTP; 12 Apr 2022 01:19:02 -0700 Received: by stinkbox (sSMTP sendmail emulation); Tue, 12 Apr 2022 11:19:02 +0300 Date: Tue, 12 Apr 2022 11:19:02 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Jani Nikula Message-ID: References: <20220405173410.11436-9-ville.syrjala@linux.intel.com> <20220406133923.30709-1-ville.syrjala@linux.intel.com> <87o81c4yyu.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87o81c4yyu.fsf@intel.com> X-Patchwork-Hint: comment Subject: Re: [Intel-gfx] [PATCH v3 08/22] drm/i915/bios: Generate LFP data table pointers if the VBT lacks them X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Apr 07, 2022 at 07:53:13PM +0300, Jani Nikula wrote: > On Wed, 06 Apr 2022, Ville Syrjala wrote: > > From: Ville Syrjälä > > > > Modern VBTs no longer contain the LFP data table pointers > > block (41). We are expecting to have one in order to be able > > to parse the LFP data block (42), so let's make one up. > > > > Since the fp_timing table has variable size we must somehow > > determine its size. Rather than just hardcode it we look for > > the terminator bytes (0xffff) to figure out where each table > > entry starts. dvo_timing, panel_pnp_id, and panel_name are > > expected to have fixed size. > > > > This has been observed on various machines, eg. TGL with BDB > > version 240, CML with BDB version 231, etc. The most recent > > VBT I've observed that still had block 41 had BDB version > > 228. So presumably the cutoff (if an exact cutoff even exists) > > is somewhere around BDB version 229-231. > > > > v2: kfree the thing we allocated, not the thing+3 bytes > > v3: Do the debugprint only if we found the LFP data block > > > > Signed-off-by: Ville Syrjälä > > --- > > drivers/gpu/drm/i915/display/intel_bios.c | 136 +++++++++++++++++++++- > > 1 file changed, 135 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c > > index 8b118c54314d..d32091dad1b0 100644 > > --- a/drivers/gpu/drm/i915/display/intel_bios.c > > +++ b/drivers/gpu/drm/i915/display/intel_bios.c > > @@ -310,16 +310,146 @@ static bool fixup_lfp_data_ptrs(const void *bdb, void *ptrs_block) > > return validate_lfp_data_ptrs(bdb, ptrs); > > } > > > > +static const void *find_fp_timing_terminator(const u8 *data, int size) > > +{ > > + int i; > > + > > + if (!data) > > + return NULL; > > + > > + for (i = 0; i < size - 1; i++) { > > + if (data[i] == 0xff && data[i+1] == 0xff) > > + return &data[i]; > > + } > > + > > + return NULL; > > +} > > + > > +static int make_lfp_data_ptr(struct lvds_lfp_data_ptr_table *table, > > + int table_size, int total_size) > > +{ > > + if (total_size < table_size) > > + return total_size; > > + > > + table->table_size = table_size; > > + table->offset = total_size - table_size; > > + > > + return total_size - table_size; > > +} > > + > > +static void next_lfp_data_ptr(struct lvds_lfp_data_ptr_table *next, > > + const struct lvds_lfp_data_ptr_table *prev, > > + int size) > > +{ > > + next->table_size = prev->table_size; > > + next->offset = prev->offset + size; > > +} > > + > > +static void *generate_lfp_data_ptrs(struct drm_i915_private *i915, > > + const void *bdb) > > +{ > > + int i, size, table_size, block_size, offset; > > + const void *t0, *t1, *block; > > + struct bdb_lvds_lfp_data_ptrs *ptrs; > > + void *ptrs_block; > > + > > + block = find_raw_section(bdb, BDB_LVDS_LFP_DATA); > > + if (!block) > > + return NULL; > > + > > + drm_dbg_kms(&i915->drm, "Generating LFP data table pointers\n"); > > + > > + block_size = get_blocksize(block); > > + > > + size = block_size; > > + t0 = find_fp_timing_terminator(block, size); > > + > > + size -= t0 - block - 2; > > + t1 = find_fp_timing_terminator(t0 + 2, size); > > Need to NULL check t0 before using it. I had the null check in find_fp_timing_terminator() but the +2 here does mean that it doesn't actually work. I'll move the check here. -- Ville Syrjälä Intel