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* [PATCH v3] usb: gadget: f_mass_storage: Make CD-ROM emulation works with Windows OS
@ 2022-06-28  2:14 Neal Liu
  2022-06-28 14:52 ` Alan Stern
  0 siblings, 1 reply; 2+ messages in thread
From: Neal Liu @ 2022-06-28  2:14 UTC (permalink / raw)
  To: Felipe Balbi, Greg Kroah-Hartman, Alan Stern
  Cc: Roger Quadros, Miaohe Lin, Wesley Cheng, Eric W . Biederman,
	Matthew Wilcox, Nikita Yushchenko, Cai Huoqing, linux-usb,
	linux-kernel, BMC-SW

Add read TOC with format 1 to support CD-ROM emulation with
Windows OS.
This patch is tested on Windows OS Server 2019.

Fixes: 89ada0fe669a ("usb: gadget: f_mass_storage: Make CD-ROM emulation work
with Mac OS-X")
Signed-off-by: Neal Liu <neal_liu@aspeedtech.com>
---
v3:
- ignore start_track value with format 1
- add fixes tags
- revise comments properly

v2:
- revise comments

 drivers/usb/gadget/function/f_mass_storage.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 3a77bca0ebe1..e884f295504f 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -1192,13 +1192,14 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
 	u8		format;
 	int		i, len;
 
+	format = common->cmnd[2] & 0xf;
+
 	if ((common->cmnd[1] & ~0x02) != 0 ||	/* Mask away MSF */
-			start_track > 1) {
+			(start_track > 1 && format != 0x1)) {
 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
 		return -EINVAL;
 	}
 
-	format = common->cmnd[2] & 0xf;
 	/*
 	 * Check if CDB is old style SFF-8020i
 	 * i.e. format is in 2 MSBs of byte 9
@@ -1208,8 +1209,8 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
 		format = (common->cmnd[9] >> 6) & 0x3;
 
 	switch (format) {
-	case 0:
-		/* Formatted TOC */
+	case 0:	/* Formatted TOC */
+	case 1:	/* Multi-session info */
 		len = 4 + 2*8;		/* 4 byte header + 2 descriptors */
 		memset(buf, 0, len);
 		buf[1] = len - 2;	/* TOC Length excludes length field */
@@ -1250,7 +1251,7 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
 		return len;
 
 	default:
-		/* Multi-session, PMA, ATIP, CD-TEXT not supported/required */
+		/* PMA, ATIP, CD-TEXT not supported/required */
 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
 		return -EINVAL;
 	}
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH v3] usb: gadget: f_mass_storage: Make CD-ROM emulation works with Windows OS
  2022-06-28  2:14 [PATCH v3] usb: gadget: f_mass_storage: Make CD-ROM emulation works with Windows OS Neal Liu
@ 2022-06-28 14:52 ` Alan Stern
  0 siblings, 0 replies; 2+ messages in thread
From: Alan Stern @ 2022-06-28 14:52 UTC (permalink / raw)
  To: Neal Liu
  Cc: Felipe Balbi, Greg Kroah-Hartman, Roger Quadros, Miaohe Lin,
	Wesley Cheng, Eric W . Biederman, Matthew Wilcox,
	Nikita Yushchenko, Cai Huoqing, linux-usb, linux-kernel, BMC-SW

On Tue, Jun 28, 2022 at 10:14:36AM +0800, Neal Liu wrote:
> Add read TOC with format 1 to support CD-ROM emulation with
> Windows OS.
> This patch is tested on Windows OS Server 2019.
> 
> Fixes: 89ada0fe669a ("usb: gadget: f_mass_storage: Make CD-ROM emulation work
> with Mac OS-X")
> Signed-off-by: Neal Liu <neal_liu@aspeedtech.com>
> ---

Reviewed-by: Alan Stern <stern@rowland.harvard.edu>

> v3:
> - ignore start_track value with format 1
> - add fixes tags
> - revise comments properly
> 
> v2:
> - revise comments
> 
>  drivers/usb/gadget/function/f_mass_storage.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
> index 3a77bca0ebe1..e884f295504f 100644
> --- a/drivers/usb/gadget/function/f_mass_storage.c
> +++ b/drivers/usb/gadget/function/f_mass_storage.c
> @@ -1192,13 +1192,14 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
>  	u8		format;
>  	int		i, len;
>  
> +	format = common->cmnd[2] & 0xf;
> +
>  	if ((common->cmnd[1] & ~0x02) != 0 ||	/* Mask away MSF */
> -			start_track > 1) {
> +			(start_track > 1 && format != 0x1)) {
>  		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
>  		return -EINVAL;
>  	}
>  
> -	format = common->cmnd[2] & 0xf;
>  	/*
>  	 * Check if CDB is old style SFF-8020i
>  	 * i.e. format is in 2 MSBs of byte 9
> @@ -1208,8 +1209,8 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
>  		format = (common->cmnd[9] >> 6) & 0x3;
>  
>  	switch (format) {
> -	case 0:
> -		/* Formatted TOC */
> +	case 0:	/* Formatted TOC */
> +	case 1:	/* Multi-session info */
>  		len = 4 + 2*8;		/* 4 byte header + 2 descriptors */
>  		memset(buf, 0, len);
>  		buf[1] = len - 2;	/* TOC Length excludes length field */
> @@ -1250,7 +1251,7 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
>  		return len;
>  
>  	default:
> -		/* Multi-session, PMA, ATIP, CD-TEXT not supported/required */
> +		/* PMA, ATIP, CD-TEXT not supported/required */
>  		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
>  		return -EINVAL;
>  	}
> -- 
> 2.25.1
> 

^ permalink raw reply	[flat|nested] 2+ messages in thread

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