linux-kernel - [PATCH] drm/amd/powerplay: return false instead of -EINVAL

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Message-Id: <20161103100924.26697-1-andrew.shadura@collabora.co.uk>
Date:   Thu,  3 Nov 2016 11:09:24 +0100
From:   Andrew Shadura <andrew.shadura@...labora.co.uk>
To:     linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        David Airlie <airlied@...ux.ie>
Cc:     Rex Zhu <Rex.Zhu@....com>, Jammy Zhou <Jammy.Zhou@....com>
Subject: [PATCH] drm/amd/powerplay: return false instead of -EINVAL

Returning -EINVAL from a bool-returning function
phm_check_smc_update_required_for_display_configuration has an unexpected
effect of returning true, which is probably not what was intended.
Replace -EINVAL by false.

The only place this function is called from is
psm_adjust_power_state_dynamic in
drivers/gpu/drm/amd/powerplay/eventmgr/psm.c:106:

	if (!equal || phm_check_smc_update_required_for_display_configuration(hwmgr)) {
		phm_apply_state_adjust_rules(hwmgr, requested, pcurrent);
		phm_set_power_state(hwmgr, &pcurrent->hardware, &requested->hardware);
		hwmgr->current_ps = requested;
	}

It seems to expect a boolean value here.

This issue has been found using the following Coccinelle semantic patch
written by Peter Senna Tschudin:
<smpl>
@@
identifier f;
constant C;
typedef bool;
@@
bool f (...){
<+...
* return -C;
...+>
}
</smpl>

Signed-off-by: Andrew Shadura <andrew.shadura@...labora.co.uk>
---
 drivers/gpu/drm/amd/powerplay/hwmgr/hardwaremanager.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/hardwaremanager.c b/drivers/gpu/drm/amd/powerplay/hwmgr/hardwaremanager.c
index 789f98a..82038b08 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/hardwaremanager.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/hardwaremanager.c
@@ -306,7 +306,7 @@ bool phm_check_smc_update_required_for_display_configuration(struct pp_hwmgr *hw
 	PHM_FUNC_CHECK(hwmgr);
 
 	if (hwmgr->hwmgr_func->check_smc_update_required_for_display_configuration == NULL)
-		return -EINVAL;
+		return false;
 
 	return hwmgr->hwmgr_func->check_smc_update_required_for_display_configuration(hwmgr);
 }
-- 
2.7.4