linux-kernel - Re: [PATCH v3] drm/i915: Honor SSC quirk table over the default, unless set by user

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Message-ID: <yunvcqtxj8c.fsf@aiko.keithp.com>
Date:	Wed, 09 Nov 2011 10:07:31 -0800
From:	Keith Packard <keithp@...thp.com>
To:	Michel Alexandre Salim <salimma@...oraproject.org>,
	intel-gfx@...ts.freedesktop.org
Cc:	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Chris Wilson <chris@...is-wilson.co.uk>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] drm/i915: Honor SSC quirk table over the default, unless set by user

On Wed, 09 Nov 2011 17:30:29 +0100, Michel Alexandre Salim <salimma@...oraproject.org> wrote:
> Additional note: while I've not touched the line since it does not
> affect me, it seems that i915_panel_use_ssc *cannot* be less than 0
> since that variable is declared as unsigned.

Oops. That's the bug here -- we're supposed to make it so that the
command line can override the quirks, but there's no way to use a quirk
given the mis-declared parameter.

This is untested...

From e64ecadef40e3c2035cd4e9b967ffd83489bdea0 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@...thp.com>
Date: Wed, 9 Nov 2011 09:57:50 -0800
Subject: [PATCH] drm/i915: Module parameters using '-1' as default must be
 signed type

Testing i915_panel_use_ssc for the default value was broken, so the
driver would never autodetect the correct value.

Signed-off-by: Keith Packard <keithp@...thp.com>
---
 drivers/gpu/drm/i915/i915_drv.c |    4 ++--
 drivers/gpu/drm/i915/i915_drv.h |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 548e04b..13488be 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -67,7 +67,7 @@ module_param_named(i915_enable_rc6, i915_enable_rc6, int, 0600);
 MODULE_PARM_DESC(i915_enable_rc6,
 		"Enable power-saving render C-state 6 (default: true)");
 
-unsigned int i915_enable_fbc __read_mostly = -1;
+int i915_enable_fbc __read_mostly = -1;
 module_param_named(i915_enable_fbc, i915_enable_fbc, int, 0600);
 MODULE_PARM_DESC(i915_enable_fbc,
 		"Enable frame buffer compression for power savings "
@@ -79,7 +79,7 @@ MODULE_PARM_DESC(lvds_downclock,
 		"Use panel (LVDS/eDP) downclocking for power savings "
 		"(default: false)");
 
-unsigned int i915_panel_use_ssc __read_mostly = -1;
+int i915_panel_use_ssc __read_mostly = -1;
 module_param_named(lvds_use_ssc, i915_panel_use_ssc, int, 0600);
 MODULE_PARM_DESC(lvds_use_ssc,
 		"Use Spread Spectrum Clock with panels [LVDS/eDP] "
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d2da91f..4a9c1b9 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1000,10 +1000,10 @@ extern int i915_panel_ignore_lid __read_mostly;
 extern unsigned int i915_powersave __read_mostly;
 extern unsigned int i915_semaphores __read_mostly;
 extern unsigned int i915_lvds_downclock __read_mostly;
-extern unsigned int i915_panel_use_ssc __read_mostly;
+extern int i915_panel_use_ssc __read_mostly;
 extern int i915_vbt_sdvo_panel_type __read_mostly;
 extern unsigned int i915_enable_rc6 __read_mostly;
-extern unsigned int i915_enable_fbc __read_mostly;
+extern int i915_enable_fbc __read_mostly;
 extern bool i915_enable_hangcheck __read_mostly;
 
 extern int i915_suspend(struct drm_device *dev, pm_message_t state);
-- 
1.7.7

-- 
keith.packard@...el.com

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