From patchwork Fri Jan 8 02:58:19 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhao, Yakui" X-Patchwork-Id: 71715 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by demeter.kernel.org (8.14.3/8.14.2) with ESMTP id o0830L4s026216 for ; Fri, 8 Jan 2010 03:00:21 GMT Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D22629E9AF; Thu, 7 Jan 2010 19:00:20 -0800 (PST) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTP id E34DE9E9AF for ; Thu, 7 Jan 2010 19:00:18 -0800 (PST) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP; 07 Jan 2010 18:59:54 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.49,239,1262592000"; d="scan'208";a="482326242" Received: from unknown (HELO localhost.localdomain) ([10.239.13.112]) by orsmga002.jf.intel.com with ESMTP; 07 Jan 2010 18:59:45 -0800 From: yakui.zhao@intel.com To: eric@anholt.net Date: Fri, 8 Jan 2010 10:58:19 +0800 Message-Id: <1262919500-18213-1-git-send-email-yakui.zhao@intel.com> X-Mailer: git-send-email 1.5.4.5 Cc: intel-gfx@lists.freedesktop.org Subject: [Intel-gfx] [PATCH 1/2] drm/i915: Read the response after issuing DDC bus switch command X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.9 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: intel-gfx-bounces@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c index de5144c..f899afd 100644 --- a/drivers/gpu/drm/i915/intel_sdvo.c +++ b/drivers/gpu/drm/i915/intel_sdvo.c @@ -462,14 +462,63 @@ static int intel_sdvo_get_pixel_multiplier(struct drm_display_mode *mode) } /** - * Don't check status code from this as it switches the bus back to the - * SDVO chips which defeats the purpose of doing a bus switch in the first - * place. + * Try to read the response after issuie the DDC switch command. But it + * is noted that we must do the action of reading response and issuing DDC + * switch command in one I2C transaction. Otherwise when we try to start + * another I2C transaction after issuing the DDC bus switch, it will be + * switched to the internal SDVO register. */ static void intel_sdvo_set_control_bus_switch(struct intel_output *intel_output, u8 target) { - intel_sdvo_write_cmd(intel_output, SDVO_CMD_SET_CONTROL_BUS_SWITCH, &target, 1); + struct intel_sdvo_priv *sdvo_priv = intel_output->dev_priv; + u8 out_buf[2], cmd_buf[2], ret_value[2], ret; + struct i2c_msg msgs[] = { + { + .addr = sdvo_priv->slave_addr >> 1, + .flags = 0, + .len = 2, + .buf = out_buf, + }, + /* the following two are to read the response */ + { + .addr = sdvo_priv->slave_addr >> 1, + .flags = 0, + .len = 1, + .buf = cmd_buf, + }, + { + .addr = sdvo_priv->slave_addr >> 1, + .flags = I2C_M_RD, + .len = 1, + .buf = ret_value, + }, + }; + + intel_sdvo_debug_write(intel_output, SDVO_CMD_SET_CONTROL_BUS_SWITCH, + &target, 1); + /* write the DDC switch command argument */ + intel_sdvo_write_byte(intel_output, SDVO_I2C_ARG_0, target); + + out_buf[0] = SDVO_I2C_OPCODE; + out_buf[1] = SDVO_CMD_SET_CONTROL_BUS_SWITCH; + cmd_buf[0] = SDVO_I2C_CMD_STATUS; + cmd_buf[1] = 0; + ret_value[0] = 0; + ret_value[1] = 0; + + ret = i2c_transfer(intel_output->i2c_bus, msgs, 3); + if (ret != 3) { + /* failure in I2C transfer */ + DRM_DEBUG_KMS("I2c transfer returned %d\n", ret); + return; + } + if (ret_value[0] != SDVO_CMD_STATUS_SUCCESS) { + DRM_DEBUG_KMS("DDC switch command returns response %d\n", + ret_value[0]); + return; + } + return; } static bool intel_sdvo_set_target_input(struct intel_output *intel_output, bool target_0, bool target_1)