On Wed, Mar 31, 2010 at 10:07 PM, Madhusudhan <madhu.cr@xxxxxx> wrote: > > >> -----Original Message----- >> From: kishore kadiyala [mailto:kishorek.kadiyala@xxxxxxxxx] >> Sent: Wednesday, March 31, 2010 2:03 AM >> To: Vimal Singh >> Cc: Madhusudhan; tony@xxxxxxxxxxx; svenkatr@xxxxxx; linux- >> omap@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; >> jarkko.lavinen@xxxxxxxxx >> Subject: Re: [PATCH-V2] OMAP: Fix for bus width which improves SD card's >> peformance. >> >> Sorry for that and here's the Updated one. >> >> From: Kishore Kadiyala <kishore.kadiyala@xxxxxx> >> >> This patch improves low speeds for SD cards. >> OMAP-MMC controller's can support maximum bus width of '8'. >> when bus width is mentioned as "8" in controller data,the SD >> stack will check whether bus width is "4" and if not it will >> set bus width to "1" and there by degrading performance. >> This patch fixes the issue and improves the performance of >> SD cards. >> >> Signed-off-by: Kishore Kadiyala <kishore.kadiyala@xxxxxx> >> Signed-off-by: Venkatraman S <svenkatr@xxxxxx> >> Acked-by: Madhusudhan Chikkature <madhu.cr@xxxxxx> >> >> --- >> In V2 : Appended Signed-off by Venkat and Ack by Madhu >> >> Here are my experiment numbers, on a Class 6 SDHC card: >> Read peformance is increased by 220% >> Write Performance is increased by 52% >> >> drivers/mmc/host/omap_hsmmc.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c >> index 83f0aff..8c97c22 100644 >> --- a/drivers/mmc/host/omap_hsmmc.c >> +++ b/drivers/mmc/host/omap_hsmmc.c >> @@ -2092,7 +2092,7 @@ static int __init omap_hsmmc_probe(struct >> MMC_CAP_WAIT_WHILE_BUSY; >> >> if (mmc_slot(host).wires >= 8) >> - mmc->caps |= MMC_CAP_8_BIT_DATA; >> + mmc->caps |= (MMC_CAP_8_BIT_DATA | MMC_CAP_4_BIT_DATA); >> else if (mmc_slot(host).wires >= 4) >> mmc->caps |= MMC_CAP_4_BIT_DATA; >> > Kishore, > > Since this patch is not yet pushed it makes sense to fix the readability > issue. > > Since 8-bit is the max how about: > > if (mmc_slot(host).wires == 8) > mmc->caps |= MMC_CAP_8_BIT_DATA | MMC_CAP_4_BIT_DATA; > if (mmc_slot(host).wires == 4) > mmc->caps |= MMC_CAP_4_BIT_DATA; > Madhu, In the above snippet, it checks whether wires are 8 or 4 and if not neither set's capability to "1". Does it make sense to check whether the wires are 8,4,1 and if not any[8,4,1] throw error and come out. Regards, Kishore > This would be little easy to read the code. > > Can you please repost the patch?? > > Regards, > Madhu > >> -- >> 1.6.3.3 > > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
