linux-kernel - [PATCH 1/4] video: msmfb: Put the partial update magic value into the fix

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Message-Id: <1299100596-11157-1-git-send-email-carlv@codeaurora.org>
Date:	Wed,  2 Mar 2011 13:16:36 -0800
From:	Carl Vanderlip <carlv@...eaurora.org>
To:	David Brown <davidb@...eaurora.org>,
	Daniel Walker <dwalker@...o99.com>,
	Bryan Huntsman <bryanh@...eaurora.org>
Cc:	Dima Zavin <dima@...roid.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
	Carl Vanderlip <carlv@...eaurora.org>,
	linux-fbdev@...r.kernel.org (open list:FRAMEBUFFER LAYER)
Subject: [PATCH 1/4] video: msmfb: Put the partial update magic value into the fix_screen struct.

From: Dima Zavin <dima@...roid.com>

This can then be tested by userspace to see if the capability is supported.
Userspace cannot rely on that value being left in var_screen, since userspace
itself can change it.

Signed-off-by: Dima Zavin <dima@...roid.com>
Signed-off-by: Carl Vanderlip <carlv@...eaurora.org>
---
 drivers/video/msm/msm_fb.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/drivers/video/msm/msm_fb.c b/drivers/video/msm/msm_fb.c
index 5436aeb..fe5efe5 100644
--- a/drivers/video/msm/msm_fb.c
+++ b/drivers/video/msm/msm_fb.c
@@ -469,6 +469,18 @@ static void setup_fb_info(struct msmfb_info *msmfb)
 	fb_info->var.yoffset = 0;
 
 	if (msmfb->panel->caps & MSMFB_CAP_PARTIAL_UPDATES) {
+		/*
+		 * Set the param in the fixed screen, so userspace can't
+		 * change it. This will be used to check for the
+		 * capability.
+		 */
+		fb_info->fix.reserved[0] = 0x5444;
+		fb_info->fix.reserved[1] = 0x5055;
+
+		/*
+		 * This preloads the value so that if userspace doesn't
+		 * change it, it will be a full update
+		 */
 		fb_info->var.reserved[0] = 0x54445055;
 		fb_info->var.reserved[1] = 0;
 		fb_info->var.reserved[2] = (uint16_t)msmfb->xres |
-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

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