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 4841CC433F5 for ; Wed, 23 Mar 2022 12:02:15 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A96D510E6BE; Wed, 23 Mar 2022 12:02:14 +0000 (UTC) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 678C410E6B6; Wed, 23 Mar 2022 12:02:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1648036933; x=1679572933; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=evxiRUn4TAwBSNziim70mF4e/AvPnuj7deM5C8FvCsY=; b=OxbnO/z33UM9lqv6mzzhiqVPL0zaBtCZGiu4rBBEBvXklxZsuaE8U2mQ DYKFQgFGYnAHqw/zSUn90lz7pK50+pNLGkm9vE1dMSDjC6H3RF2k9hxjZ XDYX2lgcxpdT9pdu1fXvHaId6IUxBZRymzw6E6tfMkYTJILj3+Uvoeixd 0hqfRLN6oQAGks4xckF3LtvMw/hg5fUHLoNSW7TBf925LluSTsNVEhjBV SiZCsedPtIKDObC142VMNtu2qsypiM9rkldiRb26hyE8zkjkodrAl/GwD TRASmwd6C1UAWtAxrBGfU6fSEvccJFiQzkxTNgnjnWtAIrBQ11fsU9aYg w==; X-IronPort-AV: E=McAfee;i="6200,9189,10294"; a="344526177" X-IronPort-AV: E=Sophos;i="5.90,204,1643702400"; d="scan'208";a="344526177" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Mar 2022 05:02:12 -0700 X-IronPort-AV: E=Sophos;i="5.90,204,1643702400"; d="scan'208";a="544165390" Received: from caliyanx-mobl.gar.corp.intel.com (HELO localhost) ([10.252.57.47]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Mar 2022 05:02:09 -0700 From: Jani Nikula To: Lee Shawn C , dri-devel@lists.freedesktop.org In-Reply-To: <8735j9j7vd.fsf@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20220317124202.14189-1-shawn.c.lee@intel.com> <20220317124202.14189-4-shawn.c.lee@intel.com> <8735j9j7vd.fsf@intel.com> Date: Wed, 23 Mar 2022 14:02:06 +0200 Message-ID: <87tuboj2rl.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Intel-gfx] [v8 3/5] drm/edid: read HF-EEODB ext block 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: cooper.chiou@intel.com, william.tseng@intel.com, Simon Ser , intel-gfx@lists.freedesktop.org, Daniel Stone Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, 23 Mar 2022, Jani Nikula wrote: > On Thu, 17 Mar 2022, Lee Shawn C wrote: >> According to HDMI 2.1 spec. >> >> "The HDMI Forum EDID Extension Override Data Block (HF-EEODB) >> is utilized by Sink Devices to provide an alternate method to >> indicate an EDID Extension Block count larger than 1, while >> avoiding the need to present a VESA Block Map in the first >> E-EDID Extension Block." >> >> It is a mandatory for HDMI 2.1 protocol compliance as well. >> This patch help to know how many HF_EEODB blocks report by sink >> and read allo HF_EEODB blocks back. > > It still just boggles my mind that they've implemented something like > this. They cite avoiding the EDID Block Map as the rationale... but it's > been optional since E-EDID structure v1.4, published in 2006. 15+ years > ago. > > Can anyone tell me a sane reason for this? What does it provide that > E-EDID 1.4 does not? Do they want to use E-EDID v1.3 with this? Why? Oh, and the main problem with the whole thing, and this implementation? If you have a struct edid *, there's no way way to tell if whoever allocated the memory or copied the block was actually HF-EEODB aware. Basically we'd have to audit every single piece of EDID handling code across all drivers to see if they handle HF-EEODB properly. If we don't, it's a question of time a struct edid * with HF-EEODB but no memory allocated for the extensions gets passed to a function that understands it, and overflows the buffer. Simon and Daniel also tell me on IRC we can't just modify the base block extension count to match HF-EEODB to dodge the problem, because the EDID gets exposed to userspace. BR, Jani. > > BR, > Jani. > > >> >> v2: support to find CEA block, check EEODB block format, and return >> available block number in drm_edid_read_hf_eeodb_blk_count(). >> >> Cc: Jani Nikula >> Cc: Ville Syrjala >> Cc: Ankit Nautiyal >> Cc: intel-gfx >> Signed-off-by: Lee Shawn C >> --- >> drivers/gpu/drm/drm_connector.c | 8 +++- >> drivers/gpu/drm/drm_edid.c | 71 +++++++++++++++++++++++++++++++-- >> include/drm/drm_edid.h | 2 +- >> 3 files changed, 74 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c >> index a50c82bc2b2f..16011023c12e 100644 >> --- a/drivers/gpu/drm/drm_connector.c >> +++ b/drivers/gpu/drm/drm_connector.c >> @@ -2129,7 +2129,7 @@ int drm_connector_update_edid_property(struct drm_connector *connector, >> const struct edid *edid) >> { >> struct drm_device *dev = connector->dev; >> - size_t size = 0; >> + size_t size = 0, hf_eeodb_blk_count; >> int ret; >> const struct edid *old_edid; >> >> @@ -2137,8 +2137,12 @@ int drm_connector_update_edid_property(struct drm_connector *connector, >> if (connector->override_edid) >> return 0; >> >> - if (edid) >> + if (edid) { >> size = EDID_LENGTH * (1 + edid->extensions); >> + hf_eeodb_blk_count = drm_edid_read_hf_eeodb_blk_count(edid); >> + if (hf_eeodb_blk_count) >> + size = EDID_LENGTH * (1 + hf_eeodb_blk_count); >> + } >> >> /* Set the display info, using edid if available, otherwise >> * resetting the values to defaults. This duplicates the work >> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c >> index ef65dd97d700..890038758660 100644 >> --- a/drivers/gpu/drm/drm_edid.c >> +++ b/drivers/gpu/drm/drm_edid.c >> @@ -1992,6 +1992,7 @@ struct edid *drm_do_get_edid(struct drm_connector *connector, >> { >> int i, j = 0, valid_extensions = 0; >> u8 *edid, *new; >> + size_t hf_eeodb_blk_count; >> struct edid *override; >> >> override = drm_get_override_edid(connector); >> @@ -2051,7 +2052,35 @@ struct edid *drm_do_get_edid(struct drm_connector *connector, >> } >> >> kfree(edid); >> + return (struct edid *)new; >> + } >> + >> + hf_eeodb_blk_count = drm_edid_read_hf_eeodb_blk_count((struct edid *)edid); >> + if (hf_eeodb_blk_count >= 2) { >> + new = krealloc(edid, (hf_eeodb_blk_count + 1) * EDID_LENGTH, GFP_KERNEL); >> + if (!new) >> + goto out; >> edid = new; >> + >> + valid_extensions = hf_eeodb_blk_count - 1; >> + for (j = 2; j <= hf_eeodb_blk_count; j++) { >> + u8 *block = edid + j * EDID_LENGTH; >> + >> + for (i = 0; i < 4; i++) { >> + if (get_edid_block(data, block, j, EDID_LENGTH)) >> + goto out; >> + if (drm_edid_block_valid(block, j, false, NULL)) >> + break; >> + } >> + >> + if (i == 4) >> + valid_extensions--; >> + } >> + >> + if (valid_extensions != hf_eeodb_blk_count - 1) { >> + DRM_ERROR("Not able to retrieve proper EDID contain HF-EEODB data.\n"); >> + goto out; >> + } >> } >> >> return (struct edid *)edid; >> @@ -3315,15 +3344,17 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid, >> #define VIDEO_BLOCK 0x02 >> #define VENDOR_BLOCK 0x03 >> #define SPEAKER_BLOCK 0x04 >> -#define HDR_STATIC_METADATA_BLOCK 0x6 >> -#define USE_EXTENDED_TAG 0x07 >> -#define EXT_VIDEO_CAPABILITY_BLOCK 0x00 >> +#define EXT_VIDEO_CAPABILITY_BLOCK 0x00 >> +#define HDR_STATIC_METADATA_BLOCK 0x06 >> +#define USE_EXTENDED_TAG 0x07 >> #define EXT_VIDEO_DATA_BLOCK_420 0x0E >> -#define EXT_VIDEO_CAP_BLOCK_Y420CMDB 0x0F >> +#define EXT_VIDEO_CAP_BLOCK_Y420CMDB 0x0F >> +#define EXT_VIDEO_HF_EEODB_DATA_BLOCK 0x78 >> #define EDID_BASIC_AUDIO (1 << 6) >> #define EDID_CEA_YCRCB444 (1 << 5) >> #define EDID_CEA_YCRCB422 (1 << 4) >> #define EDID_CEA_VCDB_QS (1 << 6) >> +#define HF_EEODB_LENGTH 2 >> >> /* >> * Search EDID for CEA extension block. >> @@ -4273,9 +4304,41 @@ static bool cea_db_is_y420vdb(const u8 *db) >> return true; >> } >> >> +static bool cea_db_is_hdmi_forum_eeodb(const u8 *db) >> +{ >> + if (cea_db_tag(db) != USE_EXTENDED_TAG) >> + return false; >> + >> + if (cea_db_payload_len(db) != HF_EEODB_LENGTH) >> + return false; >> + >> + if (cea_db_extended_tag(db) != EXT_VIDEO_HF_EEODB_DATA_BLOCK) >> + return false; >> + >> + return true; >> +} >> + >> #define for_each_cea_db(cea, i, start, end) \ >> for ((i) = (start); (i) < (end) && (i) + cea_db_payload_len(&(cea)[(i)]) < (end); (i) += cea_db_payload_len(&(cea)[(i)]) + 1) >> >> +size_t drm_edid_read_hf_eeodb_blk_count(const struct edid *edid) >> +{ >> + const u8 *cea; >> + int i, start, end, ext_index = 0; >> + >> + if (edid->extensions) { >> + cea = drm_find_cea_extension(edid, &ext_index); >> + >> + if (cea && !cea_db_offsets(cea, &start, &end)) >> + for_each_cea_db(cea, i, start, end) >> + if (cea_db_is_hdmi_forum_eeodb(&cea[i])) >> + return cea[i + 2]; >> + } >> + >> + return 0; >> +} >> +EXPORT_SYMBOL_GPL(drm_edid_read_hf_eeodb_blk_count); >> + >> static void drm_parse_y420cmdb_bitmap(struct drm_connector *connector, >> const u8 *db) >> { >> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h >> index 144c495b99c4..5549da7bd7be 100644 >> --- a/include/drm/drm_edid.h >> +++ b/include/drm/drm_edid.h >> @@ -592,6 +592,6 @@ drm_display_mode_from_cea_vic(struct drm_device *dev, >> u8 video_code); >> const u8 *drm_find_edid_extension(const struct edid *edid, >> int ext_id, int *ext_index); >> - >> +size_t drm_edid_read_hf_eeodb_blk_count(const struct edid *edid); >> >> #endif /* __DRM_EDID_H__ */ -- Jani Nikula, Intel Open Source Graphics Center