[PATCH] drm/amdgpu/pm: Account for extra separator characters in sysfs interface

[Quan, Evan]

[AMD Official Use Only - Internal Distribution Only]

Thanks. Reviewed-by: Evan Quan <evan.quan at amd.com>

-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Matt Coffin
Sent: Friday, September 4, 2020 5:06 AM
To: amd-gfx at lists.freedesktop.org
Cc: Matt Coffin <mcoffin13 at gmail.com>
Subject: [PATCH] drm/amdgpu/pm: Account for extra separator characters in sysfs interface

Currently, the the input to the pp_od_clk_voltage sysfs interface has
two adjacent separator characters, i.e. "\n\0", then we try to parse an
argument out of the empty string, whereas we really should just ignore
this case, and treat any number of adjacent separators as one separator
for arguments.

We do this here by simply skipping the argument parsing for all
empy-string arguments.

An example test case would be `echo 's  1 900' > pp_od_clk_voltage`
(note the two spaces after the 's'.

This also solves the issue where the written string ends with both a
newline, and a nul-terminator, '\n\0', as is the case for `echo 's 1
900' > pp_od_clk_voltage` since the recent rebase.

Signed-off-by: Matt Coffin <mcoffin13 at gmail.com>
---
 drivers/gpu/drm/amd/pm/amdgpu_pm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
index 65f141c777c2..9ab29c21e458 100644
--- a/drivers/gpu/drm/amd/pm/amdgpu_pm.c
+++ b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
@@ -801,6 +801,8 @@ static ssize_t amdgpu_set_pp_od_clk_voltage(struct device *dev,
 while (isspace(*++tmp_str));

 while ((sub_str = strsep(&tmp_str, delimiter)) != NULL) {
+if (strlen(sub_str) == 0)
+continue;
 ret = kstrtol(sub_str, 0, &parameter[parameter_size]);
 if (ret)
 return -EINVAL;
--
2.28.0

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